Blood Biomarkers

Hemoglobin

Hemoglobin is the iron-containing protein in red blood cells that carries oxygen from the lungs to tissues and returns carbon dioxide for exhalation. Low levels suggest anemia from iron deficiency, blood loss, or chronic disease, while high levels may indicate dehydration, smoking, or polycythemia. Standard marker on every complete blood count.

Range:Men:13.5-17.5 g/dL, Women:12.0-15.5 g/dL

MCH (Mean Corpuscular Hemoglobin)

MCH reports the average mass of hemoglobin contained in a single red blood cell, calculated from hemoglobin and red cell count. Low MCH points to iron deficiency or thalassemia (hypochromic anemia);high MCH often reflects B12 or folate deficiency producing larger cells. Used together with MCV and MCHC to classify anemia subtypes.

Range:27-33 pg

MCHC (Mean Corpuscular Hemoglobin Concentration)

MCHC measures the average concentration of hemoglobin within a given volume of red blood cells, reflecting how densely each cell is packed with oxygen-carrying protein. Low values suggest iron deficiency anemia;high values can indicate hereditary spherocytosis or lab artifact from hemolysis. Used alongside MCV to distinguish anemia types.

Range:32-36 g/dL

ABO Blood Type

ABO blood typing identifies A, B, AB, or O antigens on red cells along with Rh factor (positive or negative). It is required for safe transfusion and organ transplant matching. Epidemiologic data link non-O blood groups to a modestly higher risk of venous thromboembolism and ischemic heart disease compared with type O.

Range:A/B/AB/O, Rh+/-

Hematocrit

Hematocrit measures the percentage of blood volume made up of red blood cells after centrifugation. Low values indicate anemia from blood loss, nutritional deficiency, or marrow suppression;high values suggest dehydration, chronic hypoxia, or polycythemia vera. It tracks closely with hemoglobin on routine CBC panels.

Range:Men:38-50%, Women:35-45%

Red Blood Cell Count (RBC)

RBC count measures the number of red blood cells per microliter of blood, which carry oxygen via hemoglobin. Low counts occur with anemia, blood loss, or marrow disorders;high counts may reflect dehydration, smoking, high altitude exposure, or polycythemia. Interpreted alongside hemoglobin, hematocrit, and red cell indices.

Range:Men:4.5-5.5 million/μL, Women:4.0-5.0 million/μL

White Blood Cell Count (WBC)

WBC count measures the total number of leukocytes per microliter of blood, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Elevated counts usually reflect infection, inflammation, stress, or leukemia;low counts may indicate viral infection, marrow suppression, autoimmune disease, or chemotherapy effects.

Range:4.5-11.0 thousand/μL

Platelet Count

Platelets are cell fragments from megakaryocytes that initiate blood clotting at sites of vessel injury. Low counts (thrombocytopenia) raise bleeding risk and can result from immune disorders, liver disease, or marrow failure;high counts (thrombocytosis) occur with inflammation, iron deficiency, or myeloproliferative disease.

Range:150-400 thousand/μL

MCV, MCH, MCHC

MCV, MCH, and MCHC are red blood cell indices that describe average cell size, hemoglobin mass per cell, and hemoglobin concentration per cell. Together they classify anemia as microcytic (iron deficiency, thalassemia), normocytic (chronic disease, blood loss), or macrocytic (B12 or folate deficiency, liver disease, alcohol).

Range:MCV:80-100 fL, MCH:27-33 pg, MCHC:32-36 g/dL

RDW (Red Cell Distribution Width)

RDW quantifies the variation in size among red blood cells in a sample. Elevated RDW suggests a mixed population, often from iron, B12, or folate deficiency, recent blood loss, or marrow recovery. Higher RDW is also linked with cardiovascular events and all-cause mortality independent of anemia status.

Range:11.5-14.5%

Mean Platelet Volume (MPV)

MPV reports the average size of circulating platelets and reflects platelet production and activation. Larger platelets are younger and more reactive, so elevated MPV is associated with higher cardiovascular risk, heart attack, stroke, and diabetes complications. Low MPV can accompany marrow suppression.

Range:7.5-11.5 fL

Reticulocyte Count

Reticulocytes are immature red blood cells newly released from bone marrow, measured as a percentage of total red cells. High counts indicate active marrow response to blood loss or hemolysis;low counts suggest marrow failure, iron deficiency, or B12/folate deficiency. The reticulocyte index helps classify the cause of anemia.

Range:0.5-2.5%

Immature Granulocytes

Immature granulocytes are young neutrophil precursors (promyelocytes, myelocytes, metamyelocytes) that are normally confined to bone marrow. Their appearance in blood (a left shift) signals rapid neutrophil turnover from severe bacterial infection, sepsis, inflammation, or bone marrow stimulation, and in rare cases reflects underlying myeloid malignancy.

Range:<1% of WBC

nRBC (Nucleated Red Blood Cells)

Nucleated red blood cells are immature erythrocytes still containing their nucleus and are normally present only in bone marrow after infancy. Their presence in adult blood suggests severe marrow stress from hemolysis, hypoxia, blood loss, or marrow infiltration, and has been associated with increased mortality in critically ill patients.

Range:0/100 WBC (normally absent)

Neutrophils

Neutrophils are the most abundant white blood cells and serve as the first line of defense against bacterial and fungal infection. Elevated counts (neutrophilia) occur with bacterial infection, inflammation, stress, or steroid use;low counts (neutropenia) raise infection risk and can result from chemotherapy, viral illness, or marrow disease.

Range:40-70% or 1.5-8.0 x10^9/L

Lymphocytes

Lymphocytes include B cells that make antibodies, T cells that coordinate adaptive immunity, and natural killer cells that target virus-infected and tumor cells. Elevated counts occur with viral infection, chronic inflammation, or lymphocytic leukemia;low counts appear in HIV, steroid therapy, chemotherapy, and severe stress responses.

Range:20-40% or 1.0-4.0 x10^9/L

Monocytes

Monocytes circulate briefly in blood before entering tissues to become macrophages and dendritic cells that engulf pathogens, clear debris, and present antigens. Elevated counts are seen in chronic infection, tuberculosis, autoimmune disease, and certain leukemias;low counts can occur with severe bone marrow suppression or aplastic anemia.

Range:2-8% or 0.2-0.8 x10^9/L

Eosinophils

Eosinophils are white blood cells that release granules containing enzymes to target parasites and regulate allergic and asthmatic inflammation. Elevated counts are typical in allergies, asthma, eczema, drug reactions, parasitic infections, and some cancers and autoimmune conditions. Very high counts warrant evaluation for hypereosinophilic syndromes.

Range:1-4% or 0.04-0.4 x10^9/L

Basophils

Basophils are the rarest circulating granulocytes and release histamine and heparin during allergic and inflammatory reactions. Elevations can occur with chronic inflammation, hypothyroidism, or myeloproliferative disorders including chronic myeloid leukemia. Low counts are common during acute infection, stress, or pregnancy and rarely clinically meaningful alone.

Range:0-1% or 0-0.1 x10^9/L

Band Neutrophils

Band neutrophils are immature neutrophils with unsegmented nuclei released from bone marrow when demand for infection-fighting cells is high. Their presence in blood is called a left shift and commonly indicates acute bacterial infection, sepsis, or significant inflammation. Extreme elevations can also accompany some leukemias and marrow recovery.

Range:0-5% of WBC

Reactive Lymphocytes

Reactive or atypical lymphocytes are enlarged, activated T cells responding to viral infection or other antigenic stimulation. They are classically seen in infectious mononucleosis (EBV) and also appear with CMV, viral hepatitis, HIV seroconversion, toxoplasmosis, and drug reactions. Quantity and morphology help guide further workup.

Range:0-3% of WBC

Total Cholesterol

Total cholesterol measures the sum of LDL, HDL, and VLDL cholesterol circulating in blood. It is a baseline cardiovascular risk indicator, though LDL, HDL, and ApoB give more precise risk assessment. Values above 200 mg/dL warrant closer analysis of the full lipid panel. Levels reflect diet, genetics, liver function, and hormonal status.

Range:Desirable:<200 mg/dL, Borderline:200-239 mg/dL, High:≥240 mg/dL

LDL Cholesterol

LDL cholesterol quantifies the cholesterol carried on low-density lipoprotein particles, which deposit lipids in arterial walls and drive atherosclerosis. It is the primary modifiable target for preventing heart attack and stroke. Levels are influenced by diet, exercise, body weight, thyroid function, and genetics, and respond strongly to statins and other lipid therapies.

Range:Optimal:<100 mg/dL, Near optimal:100-129 mg/dL, Borderline high:130-159 mg/dL, High:≥160 mg/dL

HDL Cholesterol

HDL cholesterol measures the cholesterol carried on high-density lipoprotein particles, which return cholesterol from peripheral tissues to the liver for disposal. Higher levels are associated with lower cardiovascular risk, while very low HDL (under 40 mg/dL in men, 50 in women) is a risk factor. Exercise, weight loss, and reduced refined carbs tend to raise HDL.

Range:Men:>40 mg/dL, Women:>50 mg/dL, Optimal:>60 mg/dL

Triglycerides

Triglycerides are the main storage form of dietary fat circulating in blood, carried on chylomicrons and VLDL particles. Elevated fasting levels often accompany insulin resistance, metabolic syndrome, type 2 diabetes, alcohol use, and high refined-carbohydrate intake. Very high levels (over 500 mg/dL) increase risk of acute pancreatitis.

VLDL Cholesterol

VLDL cholesterol reflects cholesterol carried on very low-density lipoproteins, which transport triglycerides from the liver to peripheral tissues. Usually estimated as triglycerides divided by five, VLDL contributes to atherogenic particle burden. Elevated VLDL tracks with insulin resistance, obesity, and high-carbohydrate diets, and predicts cardiovascular risk.

Range:Normal:5-40 mg/dL

Apolipoprotein B (ApoB)

ApoB is the main structural protein on LDL, VLDL, IDL, and Lp(a) particles, with one ApoB molecule per atherogenic particle. It therefore counts the total number of plaque-forming lipoproteins and is considered a more accurate cardiovascular risk marker than LDL cholesterol, especially in people with insulin resistance, high triglycerides, or discordant LDL values.

Range:Optimal:<90 mg/dL, Desirable:<100 mg/dL, High risk:>130 mg/dL

Lipoprotein (a)

Lp(a) is an LDL-like particle with an added apolipoprotein(a) that is inherited and largely unaffected by diet or exercise. Elevated Lp(a) independently raises risk of heart attack, stroke, and calcific aortic stenosis. Because it is genetically set, a single lifetime measurement often suffices, and high values prompt more aggressive control of other cardiovascular risk factors.

Range:Desirable:<30 mg/dL, Borderline:30-50 mg/dL, High:>50 mg/dL

LDL Particle Number

LDL particle number (LDL-P) counts the total LDL particles by NMR or ion mobility, independent of how much cholesterol each particle carries. Because every LDL particle can enter the arterial wall, particle number often predicts cardiovascular events better than LDL cholesterol, particularly when LDL-C and LDL-P are discordant in metabolic syndrome or diabetes.

Range:Optimal:<1000 nmol/L, Moderate risk:1000-1299 nmol/L, High risk:≥1300 nmol/L

LDL Particle Size

LDL particle size describes whether circulating LDL is predominantly large and buoyant (Pattern A) or small and dense (Pattern B). Small dense LDL penetrates the arterial wall more easily, resists clearance, and oxidizes faster, making Pattern B more atherogenic. It often accompanies high triglycerides, low HDL, and insulin resistance.

Range:Pattern A (large):>20.5 nm, Pattern B (small):<20.5 nm

TMAO (Trimethylamine N-oxide)

TMAO is produced when gut bacteria metabolize choline, carnitine, and phosphatidylcholine from red meat, eggs, and dairy into TMA, which the liver oxidizes to TMAO. Elevated levels are independently associated with heart attack, stroke, and mortality, and may promote platelet reactivity and foam cell formation. Diet and gut microbiome changes can lower TMAO.

Range:<6.2 μM optimal

Lp-PLA2 (PLAC Test)

Lp-PLA2 is a vascular-specific inflammatory enzyme bound mostly to LDL and associated with rupture-prone arterial plaque. Elevated activity or mass levels approximately double the risk of coronary events and ischemic stroke. Unlike hs-CRP, Lp-PLA2 reflects inflammation inside the artery wall rather than systemic inflammation and may guide risk stratification.

Range:<200 ng/mL

Oxidized LDL (OxLDL)

Oxidized LDL is LDL that has undergone oxidative modification, making it readily taken up by macrophages to form foam cells in arterial walls. Elevated OxLDL reflects vascular oxidative stress and is associated with metabolic syndrome, atherosclerosis, and cardiovascular events. Diets rich in antioxidants and reductions in smoking tend to lower levels.

Range:<60 U/L optimal

Apolipoprotein A1 (ApoA1)

ApoA1 is the main protein on HDL particles and supports reverse cholesterol transport and anti-inflammatory activity. Higher ApoA1 levels are associated with lower cardiovascular risk, while low ApoA1 tracks with metabolic syndrome and atherosclerosis. ApoA1 is usually interpreted alongside ApoB to assess the balance of protective and atherogenic lipoproteins.

Range:Men:120-160 mg/dL, Women:140-180 mg/dL

Non-HDL Cholesterol

Total cholesterol minus HDL cholesterol. Represents all "bad"cholesterol including LDL, VLDL, and Lp(a).

Range:<130 mg/dL optimal

Total Cholesterol/HDL Ratio

The total cholesterol to HDL ratio compares overall cholesterol burden with protective HDL and is used as a summary cardiovascular risk index. Lower ratios suggest a healthier lipid balance, while values above 5 indicate elevated risk. The ratio is part of several cardiovascular risk calculators and can be followed to monitor treatment response alongside LDL or ApoB.

Range:<4.5 optimal, <5.0 acceptable

LDL/HDL Ratio

The LDL to HDL ratio compares atherogenic LDL directly with protective HDL and serves as a summary lipid risk measure. Lower values reflect a more favorable balance, with targets generally below 2.0 to 2.5. Lifestyle changes that reduce LDL or raise HDL, along with lipid-lowering medications, improve this ratio and tend to reduce cardiovascular events.

Range:<2.5 optimal for men, <2.0 optimal for women

ApoB/ApoA1 Ratio

The ApoB/ApoA1 ratio compares the number of atherogenic particles (ApoB) with the number of HDL particles (ApoA1) and strongly predicts cardiovascular events. In studies like INTERHEART, this ratio outperformed standard lipid panels for predicting heart attack risk worldwide. Targets vary with risk, with values near 0.7 or lower generally considered favorable.

Range:<0.8 optimal

Fasting Glucose

Fasting glucose measures blood sugar after at least eight hours without caloric intake and reflects baseline glucose regulation by insulin, liver output, and peripheral uptake. Values of 100 to 125 mg/dL define prediabetes and 126 or higher on repeat testing define diabetes. Trends over time can reveal early metabolic dysfunction before HbA1c changes.

Range:Normal:70-99 mg/dL, Prediabetes:100-125 mg/dL, Diabetes:≥126 mg/dL

Hemoglobin A1c (HbA1c)

HbA1c reflects the fraction of hemoglobin with glucose attached and estimates average blood sugar over the prior two to three months. It is the standard test for diagnosing and monitoring diabetes, with values below 5.7 percent considered normal, 5.7 to 6.4 prediabetic, and 6.5 or higher diabetic. Anemia and hemoglobin variants can distort the result.

Range:Normal:<5.7%, Prediabetes:5.7-6.4%, Diabetes:≥6.5%

Insulin

Insulin is the pancreatic hormone that drives glucose, amino acid, and fat uptake into cells and suppresses liver glucose output. Elevated fasting insulin signals insulin resistance years before fasting glucose or HbA1c rise and often accompanies obesity, fatty liver, and metabolic syndrome. Low levels may indicate beta cell failure or type 1 diabetes.

Range:Fasting:2.6-24.9 μIU/mL, Optimal:<10 μIU/mL

Uric Acid

Uric acid is the end product of purine metabolism and is excreted mainly by the kidneys. Elevated levels can crystallize in joints to cause gout and in kidneys to form stones, and are associated with hypertension, metabolic syndrome, chronic kidney disease, and cardiovascular events. Diet, alcohol, fructose, and certain drugs influence levels.

Range:metabolic syndrome

Fructosamine

Fructosamine measures glycated serum proteins, mostly albumin, and reflects average blood glucose over the prior two to three weeks. It is useful when HbA1c is unreliable, such as in hemoglobinopathies, hemolysis, or recent transfusion, and for tracking rapid changes in glucose control during pregnancy or medication adjustments.

Range:200-285 μmol/L

C-Peptide

C-peptide is released one-to-one with insulin when proinsulin is cleaved in pancreatic beta cells, so it measures endogenous insulin production even in people receiving insulin therapy. Low values suggest type 1 diabetes or advanced beta cell failure, while elevated values accompany insulin resistance, type 2 diabetes, or insulinoma.

Range:0.5-2.0 ng/mL

ALT (Alanine Aminotransferase)

ALT is an enzyme concentrated in liver cells that leaks into blood when hepatocytes are injured. It is the most liver-specific of the common transaminases and rises with fatty liver disease, viral hepatitis, alcohol use, medications (including statins and acetaminophen), and autoimmune or metabolic liver disease. Persistently elevated ALT warrants further evaluation.

Range:fatty liver disease

AST (Aspartate Aminotransferase)

AST is an enzyme found in liver, heart, skeletal muscle, kidney, and red blood cells that enters blood when these tissues are damaged. Elevations can reflect liver disease, muscle injury, heavy exercise, hemolysis, or heart events. The AST/ALT ratio helps differentiate alcoholic liver disease (ratio above 2) from other causes of hepatitis.

Range:10-40 U/L

ALP (Alkaline Phosphatase)

ALP is an enzyme found mainly in liver bile ducts and bone. Elevated levels suggest bile duct obstruction, cholestasis, bone turnover from fracture or Paget disease, or normal growth in children and pregnancy. GGT helps distinguish a liver source (GGT also high) from a bone source (GGT normal). Low ALP can indicate zinc or magnesium deficiency or hypophosphatasia.

Range:44-147 U/L

GGT (Gamma-Glutamyl Transferase)

GGT is an enzyme in liver, bile duct cells, and kidney that is sensitive to cholestasis, alcohol use, and fatty liver disease. It confirms whether an elevated ALP is coming from liver rather than bone and is a common marker of heavy alcohol intake. Elevated GGT has also been linked to oxidative stress and higher cardiovascular and mortality risk.

Range:9-48 U/L

Bilirubin (Total)

Total bilirubin measures the pigment produced when hemoglobin is broken down and processed by the liver for excretion in bile. Elevated levels cause jaundice and can result from hemolysis, Gilbert syndrome (a benign inherited variant), viral hepatitis, alcoholic or drug-induced liver injury, and bile duct obstruction. Fractionation into direct and indirect bilirubin narrows the cause.

Range:bile duct obstruction

Albumin

Albumin is the most abundant protein in blood, synthesized by the liver, and maintains oncotic pressure while transporting hormones, drugs, fatty acids, and calcium. Low levels can indicate chronic liver disease, kidney protein loss (nephrotic syndrome), malnutrition, inflammation, or malabsorption. Albumin is a strong prognostic marker in hospitalized and older patients.

Range:malnutrition

Total Protein

Total protein measures the combined concentration of albumin and globulins in blood. Low levels suggest liver disease, kidney protein loss, malnutrition, or malabsorption;high levels can reflect chronic inflammation, infection, or plasma cell disorders such as multiple myeloma. The albumin-to-globulin ratio narrows down the cause.

Range:kidney disease

Globulin

Globulins are a group of serum proteins including immunoglobulins (antibodies), complement, transport proteins, and acute phase reactants. Elevated total globulin can reflect chronic inflammation, infection, liver disease, or monoclonal gammopathies like multiple myeloma. Low values suggest immunodeficiency or protein loss and may warrant protein electrophoresis for further workup.

Range:autoimmune conditions

Lipase

Lipase is a digestive enzyme produced mainly by pancreatic acinar cells that hydrolyzes dietary triglycerides. Serum levels rise sharply in acute pancreatitis and remain elevated longer than amylase, making lipase the preferred diagnostic test. Elevations can also occur with pancreatic duct obstruction, bowel ischemia, or kidney failure that reduces clearance.

Range:10-140 U/L

De Ritis Ratio (AST/ALT)

The De Ritis ratio divides AST by ALT and helps clarify the cause of elevated liver enzymes. Ratios above 2 suggest alcoholic liver disease, while ratios below 1 are more typical of viral hepatitis or nonalcoholic fatty liver disease. Very high ratios can also accompany cirrhosis, ischemic hepatitis, and muscle injury since AST is also found in muscle.

Range:0.8-1.0 normal

Creatinine

Creatinine is a waste product from muscle breakdown of creatine phosphate that is cleared almost entirely by glomerular filtration. It is the standard marker of kidney filtration and is used with age, sex, and race to estimate GFR. Levels rise with acute or chronic kidney disease, dehydration, and high muscle mass, and fall with low muscle mass or liver disease.

Range:Men:0.74-1.35 mg/dL, Women:0.59-1.04 mg/dL

BUN (Blood Urea Nitrogen)

BUN measures the nitrogen component of urea, the main nitrogenous waste produced when the liver metabolizes protein. Elevated BUN can indicate kidney dysfunction, dehydration, high protein intake, gastrointestinal bleeding, or catabolic states;low values may reflect malnutrition, severe liver disease, or overhydration. Interpreted together with creatinine and eGFR.

Range:dehydration

eGFR (Estimated Glomerular Filtration Rate)

eGFR estimates the volume of blood filtered by the kidneys each minute, calculated from creatinine (and sometimes cystatin C) adjusted for age and sex. Values above 90 mL/min/1.73m2 are generally normal, and values under 60 for three months or longer define chronic kidney disease. eGFR is used to stage kidney disease and adjust medication dosing.

Range:>60 mL/min/1.73m², Normal:>90 mL/min/1.73m²

BUN/Creatinine Ratio

The BUN/creatinine ratio helps differentiate the cause of kidney dysfunction. Ratios above 20 suggest prerenal causes such as dehydration, heart failure, or gastrointestinal bleeding, while ratios near 10 to 15 are consistent with intrinsic kidney disease. Very low ratios can reflect severe liver disease, malnutrition, or low protein intake.

Range:10:1 to 20:1

Cystatin C

Cystatin C is a small protein produced by all nucleated cells and cleared by glomerular filtration. Because it is largely independent of muscle mass, diet, and sex, it estimates kidney function more accurately than creatinine in elderly, frail, or very muscular individuals. Elevated levels also independently predict cardiovascular events and mortality.

Range:0.53-0.95 mg/L

Albumin/Globulin Ratio (A/G)

The albumin-to-globulin ratio compares liver-made albumin with immune and transport globulins and is calculated from the total protein and albumin measurements. Low ratios can indicate chronic inflammation, autoimmune disease, liver disease, or multiple myeloma, while high ratios suggest low antibody production. It helps direct further workup such as serum protein electrophoresis.

Range:1.1-2.5

Sodium

Sodium is the main extracellular electrolyte and governs fluid balance, nerve impulse transmission, and muscle contraction. Low sodium (hyponatremia) can cause confusion, seizures, and falls and may reflect heart failure, SIADH, diuretic use, or excessive water intake;high sodium (hypernatremia) usually indicates dehydration or impaired thirst response and can cause neurologic symptoms.

Range:fluid balance

Potassium

Potassium is the main intracellular cation and is essential for heart rhythm, muscle contraction, and nerve conduction. Low potassium (hypokalemia) causes weakness, cramping, and arrhythmias and is often from diuretics, vomiting, or diarrhea;high potassium (hyperkalemia) can cause dangerous arrhythmias and usually reflects kidney dysfunction or potassium-sparing drugs.

Range:3.5-5.0 mEq/L

Chloride

Chloride is the main extracellular anion and works with sodium and bicarbonate to maintain fluid balance, blood pressure, and acid-base status. Abnormal levels often accompany kidney disease, dehydration, vomiting, or metabolic acidosis and alkalosis. Chloride is interpreted alongside sodium, bicarbonate, and the anion gap to characterize acid-base and volume disorders.

Range:96-106 mEq/L

Carbon Dioxide (CO2)

Serum CO2 on a basic metabolic panel mostly reflects bicarbonate, the major buffer maintaining blood acid-base balance. Low values suggest metabolic acidosis from diabetic ketoacidosis, lactic acidosis, kidney failure, or diarrhea, while high values indicate metabolic alkalosis from vomiting, diuretics, or respiratory compensation. It is interpreted with chloride, anion gap, and pH.

Range:23-29 mEq/L

Calcium

Calcium is the most abundant mineral in the body and is needed for bone structure, muscle contraction, nerve signaling, and blood clotting. Serum calcium is tightly regulated by parathyroid hormone and vitamin D. High levels can indicate hyperparathyroidism, malignancy, or excess vitamin D, while low levels suggest vitamin D deficiency, kidney disease, or hypoparathyroidism.

Range:8.5-10.5 mg/dL

Magnesium

Magnesium is a cofactor in more than 300 enzymatic reactions including ATP production, protein synthesis, and muscle and nerve function. Deficiency is common and can cause fatigue, cramps, arrhythmias, migraines, and insulin resistance. Low levels are seen with poor diet, alcohol use, proton pump inhibitors, diuretics, and gastrointestinal losses;high levels are rare outside kidney failure.

Range:muscle function

Zinc

Zinc is an essential trace mineral required for immune function, wound healing, taste and smell, DNA synthesis, and testosterone production. Deficiency is common in vegetarians, older adults, alcohol users, and people with GI disorders and can cause slow wound healing, hair loss, and frequent infections. Excess supplementation can deplete copper and impair immunity.

Range:60-120 mcg/dL

Copper

Copper is an essential trace mineral needed for iron metabolism, connective tissue formation, and antioxidant enzymes such as ceruloplasmin and superoxide dismutase. Deficiency can cause anemia, neutropenia, and neurologic symptoms, while excess is linked to oxidative stress and liver damage in Wilson disease. Zinc supplementation can lower copper levels over time.

Range:70-140 mcg/dL

Ceruloplasmin

Ceruloplasmin is the main copper-carrying protein in blood and functions as a ferroxidase that supports iron loading onto transferrin. Low levels are classic for Wilson disease, an inherited disorder of copper accumulation, and can also occur in severe malnutrition or liver failure. As an acute phase reactant, it can be transiently elevated during inflammation, obscuring copper deficiency.

Range:20-60 mg/dL

Phosphorus

Phosphorus is a mineral needed for bone and tooth structure, ATP energy production, and cell membrane phospholipids. High levels are typical in advanced kidney disease and hypoparathyroidism, while low levels can result from malnutrition, alcohol use, refeeding syndrome, or vitamin D deficiency and cause muscle weakness and bone pain. It is interpreted alongside calcium and PTH.

Range:2.5-4.5 mg/dL

PTH (Parathyroid Hormone)

Parathyroid hormone is secreted by the parathyroid glands in response to low serum calcium and raises calcium by mobilizing bone, increasing kidney reabsorption, and activating vitamin D. Elevated PTH occurs in primary hyperparathyroidism and secondary forms from kidney disease or vitamin D deficiency and can drive bone loss. Low PTH suggests hypoparathyroidism.

Range:15-65 pg/mL

Anion Gap

The anion gap is calculated from sodium, chloride, and bicarbonate and estimates unmeasured anions in blood. A high anion gap suggests metabolic acidosis from conditions such as diabetic ketoacidosis, lactic acidosis, kidney failure, or toxic ingestions (methanol, ethylene glycol, salicylates). A low gap can reflect hypoalbuminemia or lab error.

Range:8-12 mEq/L

RBC Magnesium

RBC magnesium measures the magnesium concentration inside red blood cells and more accurately reflects total body magnesium status than serum magnesium, which represents only a small fraction of body stores. Low levels are linked with fatigue, muscle cramps, arrhythmias, and insulin resistance, and occur with diuretics, alcohol use, and malabsorption.

Range:4.2-6.8 mg/dL

TSH (Thyroid Stimulating Hormone)

TSH is released by the pituitary to stimulate thyroid hormone production and provides negative feedback regulation of the thyroid axis. Elevated TSH typically indicates primary hypothyroidism as the pituitary tries harder to stimulate an underperforming thyroid, while low TSH suggests hyperthyroidism or central pituitary disease. TSH is the preferred first-line test for thyroid dysfunction.

Range:energy

Free T4 (Thyroxine)

Free T4 measures the unbound, biologically available form of thyroxine circulating in blood. It complements TSH in diagnosing thyroid disorders:low free T4 with high TSH confirms primary hypothyroidism, while high free T4 with suppressed TSH indicates hyperthyroidism. Unlike total T4, it is not affected by binding protein changes from pregnancy or estrogen.

Range:weight gain

Free T3 (Triiodothyronine)

Free T3 measures the unbound, biologically active thyroid hormone produced mainly by peripheral conversion of T4. T3 binds thyroid hormone receptors and drives metabolism more strongly than T4. Low free T3 despite normal TSH and T4 may indicate impaired conversion from illness, caloric restriction, or selenium deficiency, a pattern sometimes called euthyroid sick syndrome.

Range:2.3-4.2 pg/mL

TPO Antibodies (Thyroid Peroxidase)

TPO antibodies target thyroid peroxidase, an enzyme in hormone synthesis, and are the most sensitive marker of autoimmune thyroid disease. They are present in most cases of Hashimoto's thyroiditis and in many with Graves disease. Elevated TPO antibodies also predict future progression to overt hypothyroidism in people with subclinical disease.

Range:<35 IU/mL, Negative:<9 IU/mL

Thyroglobulin Antibodies

Thyroglobulin antibodies target thyroglobulin, the protein used to store thyroid hormone precursors inside follicles. They are elevated in autoimmune thyroid disease including Hashimoto's thyroiditis and Graves disease. In thyroid cancer patients after thyroidectomy, their presence interferes with thyroglobulin tumor marker measurement and is itself tracked as a surrogate for recurrence.

Range:<40 IU/mL

Iodine

Iodine is an essential trace element required for synthesizing thyroid hormones T3 and T4. Deficiency causes hypothyroidism, goiter, and, in pregnancy, impaired fetal brain development, and is still common globally. Excess iodine from supplements or medications such as amiodarone can trigger either hypothyroidism or hyperthyroidism and, in some people, autoimmune thyroiditis.

Range:52-109 μg/L, WHO optimal:100-199 μg/L

Selenium

Selenium is a trace mineral incorporated into selenoproteins including iodothyronine deiodinases that convert T4 to active T3, and glutathione peroxidases that protect the thyroid from oxidative stress. Deficiency impairs thyroid hormone conversion and may worsen autoimmune thyroid disease, while excessive supplementation is toxic. Brazil nuts, seafood, and organ meats are dietary sources.

Range:70-150 μg/L

T3 Uptake

T3 uptake is an indirect measure of how much thyroid hormone-binding protein is available to bind added labeled T3. It was historically combined with total T4 to calculate the free thyroxine index before direct free T4 assays became widely available. Results are affected by estrogen, pregnancy, and certain drugs, and the test is now used less often.

Range:24-39%

Total T4

Total T4 measures both protein-bound and free thyroxine in blood. Because more than 99 percent is bound to thyroid binding globulin, albumin, and transthyretin, total T4 is influenced by changes in binding proteins caused by pregnancy, estrogen, or liver disease. Free T4 is preferred in most clinical settings for assessing thyroid status.

Range:4.5-12.0 μg/dL

Reverse T3

Reverse T3 is an inactive metabolite of T4 produced by alternative deiodination. Levels rise during severe illness, calorie restriction, trauma, and chronic stress and may reflect a shift away from active T3 production. High reverse T3 with low or normal free T3 is sometimes called euthyroid sick syndrome and usually resolves with recovery.

Range:9.2-24.1 ng/dL

Total T3

Total T3 measures both free and protein-bound triiodothyronine. Like total T4, it is affected by changes in binding proteins and is less preferred than free T3 for routine thyroid assessment. It can still be useful in diagnosing T3 toxicosis, a form of hyperthyroidism where free T3 rises disproportionately to T4.

Range:80-200 ng/dL

Free Thyroxine Index (FTI)

The free thyroxine index is calculated from total T4 and T3 uptake and estimates free T4 when binding protein levels are altered. It was widely used before reliable direct free T4 assays and remains useful in pregnancy, estrogen therapy, and other states that affect thyroid binding globulin. Abnormal FTI parallels free T4 changes in hyper- and hypothyroidism.

Range:1.4-3.8

Total Testosterone

Total testosterone measures the combined protein-bound and free fractions of the main male sex hormone, which supports muscle mass, bone density, libido, mood, and erythropoiesis. Low levels are common with aging, obesity, and chronic illness and can cause fatigue, low libido, erectile dysfunction, and depression. Morning fasting measurement is preferred because levels vary diurnally.

Range:Men:300-1000 ng/dL, Women:15-70 ng/dL

Free Testosterone

Free testosterone is the unbound fraction of testosterone that is biologically active and can enter cells to exert its effects. It is a more accurate marker of androgen status than total testosterone when SHBG levels are altered by aging, obesity, liver disease, or estrogen use. Low free testosterone despite normal total values can still cause hypogonadal symptoms.

Range:5.0-21.0 ng/dL, or 1.5-3% of total

SHBG (Sex Hormone Binding Globulin)

SHBG is a liver-made protein that binds testosterone and estrogen and regulates how much circulates freely. Low SHBG is associated with obesity, insulin resistance, fatty liver, and hypothyroidism, while high SHBG occurs in hyperthyroidism, liver disease, and with oral estrogen use. Changes in SHBG affect the interpretation of total testosterone and estradiol.

Range:regulating how much is available for tissues to use. Low SHBG is associated with insulin resistance;high SHBG can cause symptoms of low testosterone.

Estradiol (E2)

Estradiol is the main estrogen in premenopausal women and is also produced in smaller amounts in men through aromatization of testosterone. In women it regulates menstrual cycles, reproductive tissues, bone density, and mood;in men excess estradiol can cause gynecomastia and suppress testosterone. Levels vary widely across the menstrual cycle and with menopause.

Range:Men:10-40 pg/mL, Women vary by cycle phase

PSA (Prostate Specific Antigen)

PSA is a protein produced mainly by prostate epithelial cells and released into blood. Elevated levels can indicate prostate cancer but also benign prostatic hyperplasia, prostatitis, recent ejaculation, or prostate manipulation. Rising PSA over time (velocity) and free PSA percentage help distinguish cancer from benign causes and guide biopsy decisions.

Range:prostatitis

DHEA-S

DHEA-S is the sulfated storage form of dehydroepiandrosterone, an adrenal androgen precursor for both testosterone and estrogen. Levels peak in the twenties and decline steadily with age. Low DHEA-S can reflect adrenal insufficiency and has been associated with fatigue and decreased libido, while very high values may indicate adrenal hyperplasia or tumors.

Range:fatigue

Pregnenolone

Pregnenolone is synthesized from cholesterol in the adrenal glands, gonads, and brain and serves as the master precursor to DHEA, cortisol, aldosterone, testosterone, and estrogen. Levels decline with age and chronic stress and have been linked with cognition, memory, and mood. Low levels may indicate impaired steroidogenesis in adrenal dysfunction.

Range:10-200 ng/dL

Estradiol (E2)

Estradiol is the main estrogen in premenopausal women and is also produced in smaller amounts in men through aromatization of testosterone. In women it regulates menstrual cycles, reproductive tissues, bone density, and mood;in men excess estradiol can cause gynecomastia and suppress testosterone. Levels vary widely across the menstrual cycle and with menopause.

Range:elevated estradiol can cause gynecomastia and reduced testosterone effects.

Progesterone

Progesterone is secreted mainly by the corpus luteum after ovulation and by the placenta during pregnancy. It prepares the uterine lining for implantation, maintains early pregnancy, and balances estrogen. Low luteal phase progesterone suggests anovulation or luteal insufficiency and can contribute to infertility and irregular cycles, while very high levels confirm ovulation or pregnancy.

Range:Follicular:<1.0 ng/mL, Luteal:2.0-25.0 ng/mL, Postmenopausal:<1.0 ng/mL

FSH (Follicle Stimulating Hormone)

FSH is released by the pituitary and stimulates ovarian follicle growth in women and sperm production in men. In women, FSH rises dramatically during menopause as ovarian reserve declines, and is also elevated in primary ovarian insufficiency;low FSH suggests hypothalamic or pituitary dysfunction. In men, elevated FSH can indicate testicular failure.

Range:Follicular:3.5-12.5 mIU/mL, Mid-cycle:4.7-21.5 mIU/mL, Postmenopausal:25.8-134.8 mIU/mL

LH (Luteinizing Hormone)

LH is a pituitary hormone that triggers ovulation in women and stimulates testosterone production by Leydig cells in men. The mid-cycle LH surge drives ovulation, and persistent elevation of LH relative to FSH can suggest polycystic ovary syndrome. Elevated LH in postmenopausal women reflects ovarian failure, while low LH suggests hypothalamic or pituitary dysfunction.

Range:Follicular:2.4-12.6 mIU/mL, Mid-cycle:14.0-95.6 mIU/mL, Luteal:1.0-11.4 mIU/mL

Prolactin

Prolactin is a pituitary hormone that stimulates milk production during and after pregnancy and modulates reproductive function. Elevated levels outside pregnancy suppress GnRH and cause irregular periods, infertility, galactorrhea, and reduced libido, and are often from pituitary adenomas (prolactinomas), medications (especially antipsychotics), hypothyroidism, or stress.

Range:2-29 ng/mL (non-pregnant women), 10-209 ng/mL (pregnant women)

AMH (Anti-Mullerian Hormone)

AMH is produced by granulosa cells of small ovarian follicles and reflects the remaining pool of eggs, known as ovarian reserve. It is used in fertility assessment, IVF planning, and to predict time to menopause, and unlike FSH is relatively stable across the menstrual cycle. Very high AMH can accompany polycystic ovary syndrome, while very low values suggest diminished ovarian reserve.

Range:High:>3.0 ng/mL, Normal:1.0-3.0 ng/mL, Low:<1.0 ng/mL

hs-CRP (High Sensitivity C-Reactive Protein)

High-sensitivity CRP detects low levels of C-reactive protein, an acute phase protein produced by the liver in response to inflammatory cytokines. It independently predicts cardiovascular events even when cholesterol is normal, with values below 1 mg/L considered low risk and above 3 mg/L high risk. Levels are reduced by weight loss, exercise, improved diet, and statin therapy.

Range:exercise

ESR (Erythrocyte Sedimentation Rate)

The ESR measures how quickly red blood cells settle in a standardized tube and rises when inflammatory proteins cause them to clump. It is a nonspecific marker of inflammation used in conditions such as polymyalgia rheumatica, giant cell arteritis, rheumatoid arthritis, and infection. It changes more slowly than CRP and is often interpreted together with it.

Range:autoimmune diseases

Homocysteine

Homocysteine is an amino acid intermediate in methionine metabolism that is recycled with the help of folate, vitamin B12, and vitamin B6. Elevated levels damage blood vessel lining and promote clotting and are associated with higher risk of cardiovascular disease, stroke, and dementia. B-vitamin supplementation usually lowers homocysteine, though cardiovascular benefit in trials has been modest.

Range:<10 μmol/L optimal, <15 μmol/L normal

Fibrinogen

Fibrinogen is a liver-produced clotting factor and acute phase reactant that forms the fibrin mesh of blood clots. Elevated levels increase blood viscosity and thrombotic risk and are associated with cardiovascular events and chronic inflammation. Very low values can indicate liver failure, disseminated intravascular coagulation, or inherited fibrinogen disorders and raise bleeding risk.

Range:200-400 mg/dL

Ferritin/CRP Ratio

The ferritin/CRP ratio helps separate true iron overload from inflammation-driven ferritin elevation, since ferritin is both an iron storage protein and an acute phase reactant. A low ratio (high CRP, moderately high ferritin) suggests inflammation, while a high ratio (high ferritin, low CRP) is more consistent with actual iron accumulation. Useful in chronic disease workups.

Range:No established clinical range

Vitamin D (25-Hydroxy)

25-hydroxy vitamin D is the main circulating form of vitamin D and the best marker of body stores. Adequate levels support bone mineralization, calcium absorption, immune function, and muscle strength. Deficiency is common, especially at northern latitudes and in people with limited sun exposure, and is linked with osteoporosis, falls, and higher infection risk.

Range:Deficient:<20 ng/mL, Insufficient:20-29 ng/mL, Sufficient:30-100 ng/mL, Optimal:40-60 ng/mL

Methylmalonic Acid

Methylmalonic acid accumulates when vitamin B12 is insufficient for its role as a cofactor in converting methylmalonyl-CoA to succinyl-CoA. It is a more sensitive and specific indicator of functional B12 deficiency than serum B12 alone and can detect tissue-level deficiency even when serum B12 appears normal. Levels fall with B12 repletion.

Range:0.00-0.40 nmol/mL

Vitamin B12

Vitamin B12 (cobalamin) is required for DNA synthesis, red blood cell production, and nervous system function. Deficiency causes macrocytic anemia, fatigue, glossitis, peripheral neuropathy, and cognitive changes, and is common in older adults, vegans, and people taking metformin or proton pump inhibitors. Serum B12 may miss mild deficiency, so MMA and homocysteine add value.

Range:fatigue

Folate

Folate (vitamin B9) is needed for DNA synthesis, red blood cell formation, and methylation reactions. Deficiency causes macrocytic anemia and, in pregnancy, neural tube defects, and can result from poor intake, alcohol use, malabsorption, or certain medications. Most grain products are fortified, so frank deficiency is less common today in high-income countries.

Range:>3.0 ng/mL, Optimal:7-15 ng/mL

Ferritin

Ferritin is the main intracellular iron storage protein, and a small amount circulates in blood in proportion to total body iron stores. Low ferritin is the earliest and most specific marker of iron deficiency, often preceding anemia. High ferritin can reflect iron overload (hemochromatosis), but is also an acute phase reactant that rises with inflammation, infection, and liver disease.

Range:Men:24-336 ng/mL, Women:11-307 ng/mL, Optimal:50-150 ng/mL

Iron (Serum)

Serum iron measures the iron currently bound to transferrin in blood and varies substantially during the day and with recent intake. It is interpreted together with TIBC, transferrin saturation, and ferritin to assess iron status. Low serum iron suggests deficiency or chronic disease, while high values can indicate iron overload, hemolysis, or recent supplementation.

Range:Men:65-175 μg/dL, Women:50-170 μg/dL

TIBC (Total Iron Binding Capacity)

TIBC reflects the total amount of iron that transferrin in blood can bind and serves as an indirect measure of transferrin concentration. It rises in iron deficiency as the body produces more transferrin in an effort to capture available iron, and falls in chronic disease, malnutrition, and iron overload. Used together with serum iron to calculate transferrin saturation.

Range:250-450 μg/dL

UIBC (Unsaturated Iron Binding Capacity)

UIBC measures the portion of transferrin not currently bound to iron and equals TIBC minus serum iron. It rises in iron deficiency and falls in iron overload or chronic inflammation. UIBC is often reported together with serum iron and TIBC to calculate transferrin saturation and give a fuller picture of iron balance.

Range:110-370 μg/dL

Cortisol

Cortisol is the main glucocorticoid hormone, released by the adrenal glands in response to ACTH and following a diurnal rhythm that peaks in the morning. It mobilizes glucose, modulates immune function, and supports blood pressure. Chronic elevation is seen in Cushing syndrome and severe stress, while persistently low morning cortisol suggests adrenal insufficiency.

Range:muscle loss

Omega-3 Index / Fatty Acids

The Omega-3 Index measures EPA plus DHA as a percentage of total fatty acids in red blood cell membranes. It reflects long-term omega-3 intake and is inversely associated with cardiovascular death, with targets above 8 percent linked to lowest risk. Values under 4 percent are common in Western diets and can usually be raised with oily fish or fish oil supplementation.

Range:Target:>8%, Intermediate:4-8%, Undesirable:<4%

EPA (Eicosapentaenoic Acid)

EPA is a long-chain omega-3 fatty acid found mainly in oily fish that gives rise to anti-inflammatory eicosanoids and resolvins. Higher EPA levels are associated with reduced cardiovascular events, lower triglycerides, and improved inflammatory profile. Prescription high-dose EPA has been shown to reduce cardiovascular events in high-risk patients on statin therapy.

Range:No established reference range;higher levels generally better

DHA (Docosahexaenoic Acid)

DHA is a long-chain omega-3 fatty acid concentrated in brain gray matter, retina, and sperm membranes. It supports neural development and visual function and is particularly important during pregnancy, infancy, and aging. Higher DHA intake is linked with better cognitive performance and possibly slower cognitive decline. Oily fish and algae are the main sources.

Range:No established reference range;higher levels generally better

Arachidonic Acid / EPA Ratio

The AA/EPA ratio compares arachidonic acid, an omega-6 precursor of pro-inflammatory eicosanoids, with EPA, a precursor of anti-inflammatory mediators. A high ratio indicates a pro-inflammatory fatty acid balance typical of Western diets, while a lower ratio suggests better inflammatory balance. It can be lowered by reducing omega-6-rich oils and increasing EPA intake.

Range:Target:<3:1, Ideal:1.5-3:1

Heavy Metals - Lead

Blood lead measures exposure to a heavy metal with no known safe level. Sources include old paint, contaminated water pipes, certain imported products, and occupational dust. In children, even low levels impair cognitive development;in adults, higher levels are linked to hypertension, kidney dysfunction, cardiovascular events, and neurologic symptoms.

Range:<5 μg/dL, Elevated:>5 μg/dL

Heavy Metals - Mercury

Blood mercury reflects recent exposure, most commonly from consumption of large predatory fish such as tuna, swordfish, and shark. Mercury is a neurotoxin that can cause tremor, memory problems, and in pregnancy, impaired fetal neurodevelopment. Limiting intake of high-mercury fish while maintaining lower-mercury omega-3 sources balances risk and benefit.

Range:<10 μg/L, Elevated:>10 μg/L

Creatine Kinase

Creatine kinase (CK) is an enzyme found in skeletal muscle, heart, and brain that leaks into blood when these tissues are damaged. Elevations commonly follow strenuous exercise, trauma, or intramuscular injections, and can be seen with statin-related muscle injury, inflammatory myopathies, or rhabdomyolysis. Very high levels can cause kidney injury if untreated.

Range:Men:52-336 U/L, Women:29-168 U/L

IGF-1 (Insulin-like Growth Factor)

IGF-1 is a liver-produced hormone induced by growth hormone that drives tissue growth and repair. It is used to screen for growth hormone deficiency or excess (acromegaly) since it is more stable than GH itself. Levels decline with age;low values can accompany frailty, and very high values have been associated with some cancers.

Range:Age-dependent, typical adult:100-300 ng/mL

HOMA-IR (Insulin Resistance)

HOMA-IR is calculated from fasting glucose and fasting insulin and estimates hepatic insulin resistance. Values below about 1.0 suggest good insulin sensitivity, while values above 2.0 to 2.9 indicate insulin resistance and elevated diabetes risk. HOMA-IR often detects metabolic dysfunction well before fasting glucose or HbA1c become abnormal.

Range:Optimal:<1.0, Moderate risk:1.0-2.9, High risk:>2.9

Osteocalcin

Osteocalcin is a noncollagenous protein made by osteoblasts during bone formation and is released into blood as a marker of bone turnover. Elevated levels occur during rapid bone growth, fracture healing, and high-turnover conditions such as hyperparathyroidism, while low levels suggest reduced bone formation. Its undercarboxylated form has also been linked to glucose metabolism.

Range:9-42 ng/mL

LDH (Lactate Dehydrogenase)

LDH is an enzyme present in nearly all cells that catalyzes pyruvate to lactate during anaerobic metabolism and is released when cells are damaged. Elevated serum LDH is nonspecific and occurs with hemolysis, liver disease, heart attack, kidney injury, lymphoma, and many cancers. It is used to gauge disease activity and treatment response rather than for diagnosis.

Range:140-280 U/L

Leptin

Leptin is a hormone produced by fat cells that signals satiety and long-term energy sufficiency to the hypothalamus. Obesity is typically accompanied by high leptin with leptin resistance, so signals of satiety are not effectively received. Very low leptin, as in severe calorie restriction or lipodystrophy, drives hunger, suppresses reproduction, and slows metabolism.

Range:Men:1-5 ng/mL, Women:7-13 ng/mL

Adiponectin

Adiponectin is a hormone secreted by adipose tissue that improves insulin sensitivity, reduces inflammation, and protects blood vessels. Unlike most adipokines, levels fall in obesity and metabolic syndrome, and higher adiponectin is linked with lower risk of type 2 diabetes and coronary heart disease. Exercise, weight loss, and certain medications can raise adiponectin.

Range:Men:2-30 μg/mL, Women:5-40 μg/mL

APOE Genotype

APOE genotype identifies the variants of the apolipoprotein E gene (E2, E3, E4) that influence lipid metabolism and brain function. Carrying one APOE4 allele raises Alzheimer disease risk about threefold, and two alleles raise it substantially more. APOE4 also affects LDL cholesterol and cardiovascular risk, and genotype is generally tested once because it does not change.

Range:E2/E3, E3/E3 preferred;E3/E4, E4/E4 higher risk

Omega-6 Total

Total omega-6 measures the sum of circulating omega-6 polyunsaturated fatty acids, including linoleic and arachidonic acid. Adequate omega-6 intake is required for health, but a very high omega-6 to omega-3 ratio in Western diets has been linked with a more pro-inflammatory state. Interpretation focuses on the balance with omega-3 rather than omega-6 alone.

Range:Optimal ratio Omega-6:Omega-3 <4:1

Linoleic Acid

Linoleic acid is an essential omega-6 fatty acid obtained from vegetable oils, nuts, seeds, and poultry. It is the precursor for arachidonic acid and is needed for skin barrier function, growth, and reproduction. Very high intake, especially from industrial seed oils, may contribute to a pro-inflammatory fatty acid profile when not balanced by omega-3s.

Range:No established clinical range

Arachidonic Acid

Arachidonic acid is a long-chain omega-6 fatty acid produced from linoleic acid or obtained from animal foods such as meat, eggs, and dairy. It is the precursor to pro-inflammatory eicosanoids including certain prostaglandins and leukotrienes, but also to anti-inflammatory lipoxins. Balance with EPA and DHA influences overall inflammatory tone more than absolute levels.

Range:No established clinical range;ratio to EPA more meaningful

DPA (Docosapentaenoic Acid)

DPA is an omega-3 fatty acid intermediate between EPA and DHA in the metabolic pathway and is found in fish, seafood, and some marine mammals. Observational data suggest cardiovascular and anti-inflammatory benefits similar to EPA and DHA, though it is less extensively studied. DPA can also be converted back to EPA in some tissues.

Range:No established clinical range

IGF-1 Z-Score

The IGF-1 Z-score expresses IGF-1 as standard deviations from the age- and sex-specific mean, which is useful because IGF-1 declines steeply with age. A score near zero is average for age, while values near +2 or -2 suggest growth hormone excess or deficiency, respectively. It helps avoid misclassifying normal age-related changes as disease.

Range:-2.0 to +2.0 (normal range)

ANA Screen (Antinuclear Antibodies)

The ANA screen detects antibodies directed against components of the cell nucleus and is a first-line test for systemic autoimmune disease. It is typically positive in lupus, scleroderma, Sjogren syndrome, and mixed connective tissue disease, but low-titer positives also occur in healthy older adults. A positive result usually prompts specific antibody testing to identify the underlying condition.

Range:Negative (titer <1:40)

ANA Titer

ANA titer reports the highest dilution of serum at which antinuclear antibodies are still detectable and quantifies the strength of a positive ANA. Higher titers (for example 1:320 or greater) are more likely to reflect true autoimmune disease, while low titers (1:40 to 1:80) can occur in healthy people. Titer is interpreted alongside pattern and specific autoantibodies.

Range:Negative:<1:40, Positive:≥1:80

ANA Pattern

ANA pattern describes the staining distribution seen under immunofluorescence and offers clues about which nuclear antigens are targeted. Homogeneous patterns are associated with lupus and drug-induced lupus, speckled with mixed connective tissue disease and Sjogren syndrome, nucleolar with scleroderma, and centromere with limited scleroderma. Pattern plus titer guides further antibody testing.

Range:Varies by pattern and disease

Rheumatoid Factor (RF)

Rheumatoid factor is an antibody targeting the Fc portion of IgG and is positive in most patients with rheumatoid arthritis. It is not specific and can also occur in Sjogren syndrome, cryoglobulinemia, chronic infections such as hepatitis C and endocarditis, and in some healthy older adults. Higher titers correlate with more aggressive rheumatoid disease.

Range:<14 IU/mL, Weakly positive:14-40 IU/mL, Positive:>40 IU/mL

Celiac Disease Panel (Comprehensive)

Celiac serology typically includes tissue transglutaminase IgA (tTG-IgA) with total IgA to detect IgA deficiency, along with deamidated gliadin peptide antibodies when needed. These tests screen for celiac disease, an autoimmune reaction to dietary gluten. Testing must be done while eating gluten for accurate results, and positive results usually lead to confirmatory intestinal biopsy.

Range:tTG-IgA <4 U/mL negative

PSA Free (Prostate Cancer)

Free PSA measures the portion of prostate-specific antigen not bound to plasma proteins and is used alongside total PSA to refine prostate cancer risk. A higher percentage of free PSA suggests benign prostate enlargement, while a lower percentage raises concern for cancer. It helps reduce unnecessary biopsies when total PSA is only modestly elevated.

Range:Free/Total PSA ratio >25% suggests benign disease

CEA (Carcinoembryonic Antigen)

CEA is a glycoprotein normally produced during fetal development that can be re-expressed by some cancers, especially colorectal carcinoma. It is used to monitor treatment response and detect recurrence rather than to screen, since it is also elevated in smokers, inflammatory bowel disease, liver disease, and other GI cancers. Rising CEA after surgery warrants imaging.

Range:Non-smoker:<3.0 ng/mL, Smoker:<5.0 ng/mL

CA-125 (Ovarian Cancer)

CA-125 is a glycoprotein expressed by many ovarian cancers and is used to monitor treatment response and detect recurrence. It is not reliable for general screening because it is elevated in benign conditions such as endometriosis, fibroids, pelvic inflammatory disease, and menstruation, and is also a nonspecific marker in some other cancers. Trends over time carry more weight than single values.

Range:fibroids

CA 19-9 (Pancreatic/GI Cancer)

CA 19-9 is a tumor-associated antigen often elevated in pancreatic, biliary, and other gastrointestinal cancers. It is primarily used to monitor treatment response and recurrence rather than for screening, because it is also elevated in pancreatitis, cholangitis, and cholestasis and is not produced at all in people with certain blood group antigens.

Range:<37 U/mL

AFP (Alpha-Fetoprotein - Liver Cancer)

Alpha-fetoprotein is a fetal protein that normally falls to low levels after birth and can be re-expressed by hepatocellular carcinoma and germ cell tumors. It is used to screen high-risk patients with cirrhosis or chronic hepatitis B and C for liver cancer and to monitor treatment response. Mild elevations can also occur with active hepatitis or pregnancy.

Range:<10 ng/mL, Elevated:>400 ng/mL suggests cancer

Galleri Multi-Cancer Test (50+ cancers)

The Galleri test analyzes cell-free DNA methylation patterns in blood to screen for signals from more than 50 cancer types. It is designed as an add-on to standard screening rather than a replacement and aims to detect cancers that lack routine screening tests. Positive results suggest a cancer signal and predicted tissue of origin, guiding targeted imaging and workup.

Range:Negative result preferred;positive requires imaging

Neutrophil/Lymphocyte Ratio

The neutrophil-to-lymphocyte ratio is calculated from a standard CBC differential and reflects the balance between innate inflammatory and adaptive immune responses. Elevated ratios indicate systemic inflammation and stress and have been associated with worse outcomes in cardiovascular disease, cancer, infection, and critical illness. It is a simple, inexpensive marker of immune activation.

Range:Normal:<3.0, Elevated:>3.0

Platelet/Lymphocyte Ratio

The platelet-to-lymphocyte ratio combines platelet and lymphocyte counts from a standard CBC and reflects inflammation and platelet activation. Elevated values have been linked with worse prognosis in several cancers, cardiovascular events, and inflammatory diseases. It complements other simple CBC-derived ratios such as the neutrophil/lymphocyte ratio.

Range:Normal:<180, Elevated:>180

Monocyte/HDL Ratio

The monocyte-to-HDL ratio is an emerging cardiovascular risk marker that combines pro-inflammatory monocyte counts with protective HDL cholesterol. Elevated ratios reflect an imbalance favoring vascular inflammation and have been associated with coronary artery disease, metabolic syndrome, and adverse cardiovascular events. It can be calculated from standard lipid and CBC results.

Range:Optimal:<0.3, Elevated:>0.4

LDL-P (LDL Particle Number)

LDL-P counts the total number of LDL particles in blood using NMR spectroscopy and is independent of the cholesterol carried by each particle. Because each LDL particle can enter the arterial wall, LDL-P often predicts cardiovascular events better than LDL-C, especially when the two are discordant. It is useful for refining risk in metabolic syndrome and insulin resistance.

Range:Optimal:<1000 nmol/L, High risk:>1300 nmol/L

LDL Particle Size Analysis

LDL particle size analysis characterizes whether LDL in blood is mainly large buoyant (Pattern A) or small dense (Pattern B). Small dense LDL is more atherogenic because it penetrates the arterial wall more easily and oxidizes faster, and it often accompanies high triglycerides, low HDL, and insulin resistance. Knowing particle size helps refine cardiovascular risk.

Range:Pattern A (large):>20.5 nm preferred

HDL Subfractions (Large/Small)

HDL subfraction testing separates HDL into larger, more mature particles (HDL2) and smaller precursor particles (HDL3). Large HDL particles are generally considered more cardioprotective because they efficiently carry cholesterol back to the liver, while functional quality may matter more than absolute numbers. Subfractions add detail to HDL-C for cardiovascular risk assessment.

Range:Large HDL-2 preferred for cardioprotection

Transferrin Saturation

Transferrin saturation is the percentage of iron-binding sites on transferrin that are occupied and is calculated from serum iron divided by TIBC. Low values indicate iron deficiency, while values above about 45 percent suggest iron overload conditions such as hereditary hemochromatosis. It is interpreted together with ferritin for a complete picture of iron status.

Range:Men:20-50%, Women:15-50%

GGT/HDL Ratio

The GGT/HDL ratio combines a liver enzyme sensitive to fatty liver and alcohol exposure with protective HDL cholesterol. Elevated ratios have been associated with metabolic syndrome, insulin resistance, fatty liver disease, and cardiovascular risk. It offers a simple way to combine hepatic and cardiometabolic information from a standard lipid panel and liver function tests.

Range:Optimal:<0.3, Elevated:>0.4

Systemic Inflammation Index (SII)

The Systemic Inflammation Index is calculated from platelet, neutrophil, and lymphocyte counts on a standard CBC. It reflects combined inflammatory and thrombotic activity and has been linked with cardiovascular events, cancer prognosis, and overall mortality. SII offers more information than single cell counts and can be tracked over time to follow inflammation.

Range:<500 optimal, >1000 elevated

Free Androgen Index (FAI)

The Free Androgen Index is calculated from total testosterone and SHBG and estimates the proportion of biologically available testosterone. It is particularly useful in women to evaluate hirsutism, acne, and polycystic ovary syndrome, where an elevated FAI reflects functional androgen excess. In men it is a secondary measure when SHBG levels are abnormal.

Range:Men:14.8-94.8, Women:0.8-11.0

Testosterone/Estradiol Ratio

The testosterone-to-estradiol ratio reflects the balance between androgen and estrogen activity, largely set by the aromatase enzyme that converts testosterone to estradiol. Low ratios in men can accompany obesity, aging, and alcohol use and may contribute to low libido, erectile dysfunction, and gynecomastia. Weight loss and aromatase-related interventions can improve the ratio.

Range:erectile dysfunction

Urine Appearance

Urine appearance describes clarity on visual inspection and is normally clear to slightly hazy. Cloudy or turbid urine can indicate infection with bacteria and white blood cells, crystals, mucus, or contaminating vaginal secretions. Appearance is always interpreted alongside other urinalysis findings such as leukocyte esterase, nitrite, and microscopic examination.

Range:Clear

Urine Albumin

Urine albumin measures leakage of the serum protein albumin through the glomerular filter. Small elevations (microalbuminuria, 30 to 300 mg/g creatinine) are an early sign of diabetic and hypertensive kidney damage and independently predict cardiovascular events. Larger elevations (macroalbuminuria) indicate established kidney disease and warrant aggressive blood pressure and glucose control.

Range:<30 mg/g creatinine

Urine Color

Urine color reflects concentration of urochrome pigment, hydration status, diet, medications, and disease. Pale yellow suggests good hydration, while dark amber indicates concentrated urine from low fluid intake. Red or cola-colored urine can signal blood or myoglobin, orange may reflect bilirubin or certain drugs, and unusual colors warrant further investigation.

Range:Light yellow to amber

Urine pH

Urine pH measures the acidity or alkalinity of urine and normally ranges from about 4.5 to 8.0, shifting with diet, medications, and acid-base balance. Persistently acidic urine favors uric acid and cystine stone formation, while alkaline urine promotes struvite and calcium phosphate stones and may suggest urinary tract infection with urease-producing bacteria or renal tubular acidosis.

Range:4.5-8.0

Urine Specific Gravity

Urine specific gravity measures how concentrated urine is compared with pure water and reflects the kidney's ability to concentrate or dilute urine. Low values suggest overhydration or impaired concentrating ability in diabetes insipidus, while high values indicate dehydration, glycosuria, or proteinuria. It is interpreted together with clinical hydration status and other urinalysis findings.

Range:1.005-1.030

Urine Protein

Dipstick urine protein detects mainly albumin and is an early warning of kidney damage, especially in diabetes and hypertension. Persistent proteinuria is a strong risk factor for progressive kidney disease and cardiovascular events. Transient proteinuria can also occur with fever, exercise, or dehydration, so confirmed findings on repeat testing guide further workup and treatment.

Range:Negative

Urine Glucose

Urine glucose is normally absent because the kidneys reabsorb filtered glucose until blood glucose exceeds about 180 mg/dL. A positive result usually indicates uncontrolled diabetes, though it can also occur in pregnancy, with certain medications (including SGLT2 inhibitors), and in rare renal tubular disorders. Blood glucose and HbA1c testing confirm the underlying cause.

Range:Negative

Urine Ketones

Urinary ketones appear when the body shifts to burning fat for energy and acetoacetate, beta-hydroxybutyrate, and acetone spill into urine. Ketonuria occurs with fasting, low-carbohydrate diets, prolonged vomiting, and, most importantly, diabetic ketoacidosis, a serious complication of uncontrolled diabetes. The finding is interpreted alongside blood glucose, bicarbonate, and clinical status.

Range:Negative

Urine Bilirubin

Urinary bilirubin indicates conjugated bilirubin spilling into urine and is normally absent. Its presence suggests hepatobiliary disease such as viral or drug-induced hepatitis, cirrhosis, or bile duct obstruction from stones or tumors. Because conjugated bilirubin appears in urine before jaundice is visible, it can offer early evidence of liver dysfunction.

Range:Negative

Urine Blood (Occult)

Occult blood on a urine dipstick detects hemoglobin, myoglobin, or intact red blood cells that are not visible to the eye. Positive results warrant microscopic examination and may indicate urinary tract infection, kidney stones, glomerulonephritis, trauma, rhabdomyolysis, or urothelial cancer. Persistent hematuria should prompt imaging and sometimes cystoscopy to identify the source.

Range:Negative

Urine Nitrite

Urine nitrite detects bacterial conversion of dietary nitrate to nitrite and indicates a urinary tract infection when positive. It is highly specific for infection with gram-negative organisms such as E. coli, but sensitivity is lower because not all bacteria produce nitrites and the urine needs time in the bladder for the reaction. Interpretation is paired with leukocyte esterase.

Range:Negative

Urine Leukocyte Esterase

Leukocyte esterase is an enzyme released by white blood cells in urine, and a positive dipstick indicates the presence of pyuria. Together with urine nitrite it is used to screen for urinary tract infection, though positive results can also occur with kidney inflammation, interstitial nephritis, and nearby pelvic or vaginal infections. A urine culture is used to confirm and identify the organism.

Range:Negative

Urine WBC

White blood cells seen on microscopic examination of urine indicate inflammation or infection somewhere along the urinary tract. They are common in cystitis and pyelonephritis but can also appear with kidney stones, interstitial nephritis, tuberculosis, and sexually transmitted infections. Interpretation considers bacteria, nitrites, leukocyte esterase, and clinical symptoms.

Range:0-5 cells/HPF

Urine RBC

Red blood cells on microscopic urinalysis indicate hematuria, which can be microscopic or gross. Causes range from benign (menstruation, exercise) to serious (kidney stones, urinary tract infection, glomerulonephritis, bladder or kidney cancer). Persistent microscopic hematuria usually warrants imaging and sometimes cystoscopy, especially in older adults and smokers.

Range:0-3 cells/HPF

Urine Bacteria

Bacteria seen on microscopic urinalysis, in combination with leukocytes and nitrites, support a diagnosis of urinary tract infection. Because bacteria can also come from contamination during collection, a clean-catch or catheterized sample plus urine culture is used to confirm infection and identify the organism and its antibiotic sensitivities before treatment.

Range:None or few (normal)

Squamous Epithelial Cells (Urine)

Squamous epithelial cells line the distal urethra and external genitalia. Their presence in large numbers on urine microscopy usually reflects contamination during collection rather than urinary tract disease. A repeat clean-catch or catheterized specimen may be needed to obtain a sample that accurately represents the bladder and upper tract.

Range:Few or none

Transitional Epithelial Cells (Urine)

Transitional epithelial cells line the bladder, ureters, and renal pelvis, and a small number are normal in urine. Increased numbers can follow catheterization, infection, or inflammation, and rarely indicate transitional cell carcinoma of the urothelium. Marked increases or abnormal morphology may prompt cytology and imaging to rule out malignancy.

Range:Few or none

Renal Epithelial Cells (Urine)

Renal tubular epithelial cells line the kidney tubules and are normally absent or very rare in urine. Their presence suggests tubular injury from acute tubular necrosis, nephrotoxic drugs, heavy metal exposure, or viral infection. Large numbers or renal tubular casts signal significant kidney damage and prompt further evaluation of kidney function.

Range:None (normal)

Hyaline Casts (Urine)

Hyaline casts are clear cylindrical structures formed from Tamm-Horsfall protein in the renal tubules. Small numbers are normal, especially after dehydration, strenuous exercise, or diuretic use. Unlike cellular or granular casts, hyaline casts alone rarely indicate significant kidney disease and are usually considered a benign finding.

Range:0-2 per LPF

Granular Casts (Urine)

Granular casts are tubular casts containing cellular debris or protein aggregates from degenerating renal tubular cells. Coarse granular casts suggest acute tubular injury, such as from ischemia or nephrotoxins, while fine granular casts can occur in chronic kidney disease. Their presence generally warrants evaluation of kidney function and additional urinalysis findings.

Range:None (normal)

Urine Crystals

Urine crystals form when minerals and metabolites precipitate out of solution, and the type of crystal helps identify stone risk and metabolic disorders. Calcium oxalate is most common, uric acid crystals accompany gout, triple phosphate (struvite) can indicate infection, and cystine suggests a hereditary disorder. Hydration and dietary changes reduce most crystal formation.

Range:None or few

Calcium Oxalate Crystals (Urine)

Calcium oxalate crystals are the most common type seen in urine and are associated with the majority of kidney stones. Risk factors include dehydration, high-oxalate foods (spinach, rhubarb, nuts, chocolate), high sodium and animal protein intake, and certain metabolic conditions. Adequate fluid intake, dietary adjustments, and calcium intake with meals reduce stone formation.

Range:None (normal)

Uric Acid Crystals (Urine)

Uric acid crystals form in acidic urine when uric acid concentration is high and can indicate gout or uric acid kidney stones. Risk factors include high purine intake (red meat, organ meats, shellfish, beer), dehydration, metabolic syndrome, and certain medications. Hydration, urine alkalinization, and urate-lowering therapy reduce crystal formation and stone risk.

Range:None (normal)

Triple Phosphate Crystals (Urine)

Triple phosphate, or struvite, crystals form in alkaline urine from magnesium ammonium phosphate and are often associated with urinary tract infections caused by urease-producing bacteria such as Proteus, Klebsiella, and Pseudomonas. They can grow into large staghorn stones that require surgical removal. Treatment targets the underlying infection and stone burden.

Range:None (normal)

Yeast (Urine)

Yeast organisms, most commonly Candida species, in urine can reflect contamination from vaginal flora, a true urinary tract yeast infection, or systemic candidiasis. It is more common in people with diabetes, those on broad-spectrum antibiotics, immunocompromised patients, and those with indwelling urinary catheters. Clinical context and repeat testing help distinguish contamination from true infection.

Range:None (normal)

Reducing Substances (Urine)

The urine reducing substances test detects sugars other than glucose, such as galactose, fructose, and lactose, using the Clinitest copper reduction method. It is used in infants to screen for inborn errors of metabolism such as galactosemia, where early detection and dietary intervention prevent severe complications. In adults it is rarely used but can flag hereditary fructose intolerance.

Range:Negative

LDL Small

Small dense LDL particles penetrate the arterial intima more easily, oxidize readily, and clear more slowly from blood than larger LDL. High concentrations raise cardiovascular risk even when total LDL cholesterol looks normal and commonly accompany high triglycerides, low HDL, and insulin resistance. Lifestyle changes and triglyceride-lowering therapy tend to reduce them.

Range:Varies by lab methodology

LDL Medium

Medium-sized LDL particles sit between large buoyant and small dense LDL in advanced subfraction analysis. Their atherogenic potential is intermediate, and their share of total LDL helps characterize the overall LDL distribution. Values are interpreted alongside small dense LDL, LDL peak size, and overall LDL particle number for refined cardiovascular risk assessment.

Range:Varies by lab methodology

LDL Pattern

LDL pattern classifies the predominant LDL particle type as Pattern A (large buoyant LDL, lower risk) or Pattern B (small dense LDL, higher risk). Pattern B is linked with insulin resistance, high triglycerides, and low HDL and raises cardiovascular risk independently of total LDL. Carbohydrate restriction, weight loss, and exercise can shift pattern B toward pattern A.

Range:Pattern A (preferred)

LDL Peak Size

LDL peak size reports the diameter of the most common LDL particle in a sample, measured in angstroms. A peak size above roughly 263 Å indicates predominantly large buoyant LDL (Pattern A, lower risk), while smaller peak sizes signify small dense LDL (Pattern B, higher risk). It refines cardiovascular risk beyond standard LDL cholesterol.

Range:>263 Å (Pattern A)

Omega-6/Omega-3 Ratio

The omega-6 to omega-3 ratio compares intake and circulating levels of pro-inflammatory-leaning omega-6 fats with anti-inflammatory omega-3 fats. Typical Western diets produce ratios of 15:1 or higher, while ancestral and Mediterranean-style diets are closer to 2:1 to 4:1. Lower ratios are associated with lower inflammation and cardiovascular risk in observational studies.

Range:2:1 to 4:1 (optimal)

Amylase

Amylase is a digestive enzyme produced mainly by the pancreas and salivary glands that breaks dietary starches into sugars. Elevated serum amylase occurs in acute pancreatitis, pancreatic duct obstruction, salivary gland disease, and bowel perforation. Lipase is more specific for pancreatic disease and is usually measured alongside amylase when pancreatitis is suspected.

Range:28-100 U/L