The TestWell Biomarker Library

The least common white blood cell, involved in allergic and inflammatory responses.

White blood cells involved in allergic responses and parasitic infections.

A protein that binds free hemoglobin from broken-down red cells. Drops when red cells are being destroyed faster than normal.

The percentage of your blood made up of red blood cells.

The protein in red blood cells that carries oxygen from your lungs to the rest of your body.

White blood cells central to your immune response, especially against viruses.

The average amount of hemoglobin per red blood cell.

The concentration of hemoglobin within your red blood cells.

The average size of your red blood cells. Helps classify the type of anemia when one is present.

White blood cells that mature into macrophages and clean up debris and pathogens.

The average size of your platelets. Larger platelets are typically younger and more active.

The most common type of white blood cell. The first responders to bacterial infection.

The cells responsible for blood clotting. Both too few and too many can cause clotting problems.

How much your red blood cells vary in size. Elevations often appear early in nutritional deficiencies.

The number of oxygen-carrying red cells in your blood.

The percentage of red blood cells that are immature (newly produced).

Newly formed red blood cells. Reflects how actively your marrow is producing red cells.

The number of infection-fighting cells in your blood. Changes can reflect infection, inflammation, or marrow activity.

A byproduct of insulin production. Reflects how much insulin your pancreas is making, not how much you've injected.

How much insulin your pancreas is releasing at rest. High values often indicate insulin resistance.

Your average blood sugar over the past 2–3 months. The gold standard for diabetes screening and monitoring.

A 0–100 insulin-resistance score derived from lipoprotein particle sizes and counts. Higher scores indicate more insulin resistance; it often rises years before fasting glucose or A1c change.

A protein produced by the fetal liver. Used as a tumor marker in adults and a screening marker in pregnancy.

Which two copies of the APOE gene you inherited (ε2, ε3 or ε4). The ε4 variant is associated with higher LDL cholesterol and a higher lifetime risk of late-onset Alzheimer's disease; ε2 with lower LDL and lower Alzheimer's risk. A genotype is a risk factor, not a diagnosis.

The main structural protein of HDL particles. Read with ApoB: the ApoB/ApoA-1 ratio compares atherogenic to protective particles and is one of the strongest lipid predictors of heart attack.

The protein on every atherogenic lipoprotein particle. A direct count of plaque-forming particles.

A protein elevated in pancreatic and biliary tract cancers. Also rises with benign biliary disease.

A protein elevated in many ovarian cancers. Also rises with benign conditions like endometriosis or menstruation.

A protein elevated in some cancers. Most often used to monitor colorectal cancer treatment.

An omega-3 fatty acid concentrated in the brain and retina. Important for neurological function.

An omega-3 fatty acid from fish and algae oils. Has anti-inflammatory and cardiovascular effects.

The fraction of PSA not bound to other proteins. Helps distinguish benign prostate enlargement from cancer when total PSA is borderline.

The "good" cholesterol — helps remove excess cholesterol from arteries. Higher is generally better.

The actual count of HDL particles. Higher counts are associated with lower cardiovascular risk.

The average diameter of your HDL particles. Larger HDL is the more protective, cholesterol-laden form.

An amino acid that can damage blood vessels at high levels. Tied to B vitamin status (B12, folate, B6).

The count of large HDL particles — the HDL subclass most consistently associated with cardiovascular protection.

The count of large, triglyceride-rich VLDL particles. High counts accompany insulin resistance, high triglycerides and small dense LDL.

The "bad" cholesterol that contributes to plaque in arteries. Lower is generally better.

The actual count of LDL particles. A more direct measure of atherogenic burden than LDL cholesterol.

The average diameter of your LDL particles. Larger is generally healthier.

Whether your LDL particles are predominantly large and buoyant (Pattern A) or small and dense (Pattern B). Pattern B travels with high triglycerides and insulin resistance and carries higher cardiovascular risk at the same LDL cholesterol.

A simple ratio combining LDL and HDL into one risk number. Lower is generally better.

A genetically-determined cholesterol particle that carries independent cardiovascular risk.

The count of intermediate-size LDL particles, between the large buoyant and small dense subclasses.

An enzyme released by activated white blood cells inside inflamed artery walls. Elevated MPO indicates active vascular inflammation and has been associated with plaque more prone to rupture.

All your cholesterol minus HDL. Captures every atherogenic particle in one number.

A hormone fragment released when the heart is stretched. The standard marker of heart-failure status.

The percentage of EPA + DHA in your red blood cell membranes. A long-term marker of omega-3 status.

A protein made by the prostate. Screens for prostate inflammation, enlargement, or cancer.

The count of small HDL particles, the less protective HDL subclass.

The count of small, dense LDL particles — the most atherogenic LDL subtype.

A metabolite produced when gut bacteria break down choline and carnitine from the diet and the liver oxidizes the result. Higher TMAO has been associated with cardiovascular and kidney risk independent of cholesterol.

The sum of all cholesterol types in your blood. One marker of cardiovascular risk.

Fats stored from extra calories. Best measured fasting; influenced heavily by diet and alcohol.

Very-low-density lipoprotein cholesterol — mostly carries triglycerides. Calculated as triglycerides ÷ 5 in standard panels.

The average diameter of your VLDL particles; larger VLDL reflects a higher triglyceride load.

A fat-cell hormone with anti-inflammatory and insulin-sensitizing effects. Lower levels are linked to insulin resistance.

An adrenal hormone that controls sodium, potassium, and blood pressure.

A hormone produced by ovarian follicles. Used as a marker of ovarian reserve in women.

Your primary stress hormone, naturally highest in the morning. Reflects adrenal gland function.

Afternoon cortisol — should be considerably lower than morning levels in a normal diurnal pattern.

An adrenal hormone that serves as a precursor for sex hormones. Naturally declines with age.

A potent androgen made from testosterone. Drives male-pattern hair growth and prostate activity.

The primary form of estrogen. Levels vary widely with menstrual cycle, age, and reproductive stage.

The biologically active, unbound fraction of testosterone. Often more clinically meaningful than total.

A pituitary hormone that drives sex-hormone production. In women it varies dramatically through the menstrual cycle and rises sharply at menopause.

Reflects growth hormone activity. Naturally declines with age.

A hormone produced by fat cells that signals satiety. Levels generally track body fat percentage.

A pituitary hormone that triggers ovulation in women and testosterone production in men. Cycle-dependent in women.

The first steroid hormone made from cholesterol — the precursor to cortisol, DHEA, progesterone, testosterone and estrogen. Read with DHEA-S, cortisol and the sex hormones rather than alone.

A female sex hormone that prepares the uterus for pregnancy. Rises sharply after ovulation.

A pituitary hormone primarily involved in milk production. Also affects menstrual function and fertility.

A hormone that controls calcium balance by acting on bone and kidneys.

A protein that binds sex hormones. Affects how much testosterone and estrogen are biologically active.

The total amount of testosterone in circulation, both bound and unbound.

A general marker of inflammation. The standard CRP test is less sensitive than hs-CRP and is used when active inflammation is suspected.

A non-specific marker of inflammation. Slow to rise and slow to fall.

A sensitive marker of low-grade inflammation. Used for cardiovascular risk assessment.

An antibody often present in rheumatoid arthritis. Also seen in other autoimmune and infectious conditions.

An antibody that defends mucosal surfaces (gut, airways). Used to evaluate immune deficiencies and validate other antibody tests.

An enzyme released by mast cells. Used to evaluate mast cell disorders and severe allergic reactions.

The primary blood test for celiac disease. Looks for antibodies against tissue transglutaminase.

The protein that stores iron in your body. The single best marker of iron stores.

The amount of iron circulating in your blood at the moment. Varies through the day.

The percentage of your iron-binding capacity currently being used. Iron divided by TIBC.

The total capacity of your blood proteins to carry iron. Rises when iron is scarce.

The protein that carries iron in the blood. Levels rise when iron stores are low.

How long it takes blood to clot via the intrinsic pathway. Used to monitor heparin therapy and screen for clotting disorders.

The most abundant protein in blood. Made by the liver; reflects nutrition and liver/kidney health.

Urine albumin standardized by urine creatinine. The standard screen for early kidney damage.

An enzyme present in liver, bone, and bile ducts. Used to evaluate liver and bone health.

An enzyme found mainly in the liver. Elevations can signal liver cell injury.

An enzyme made by the pancreas and salivary glands that helps digest carbohydrates.

Blood arsenic reflects exposure over the preceding days — from well water, rice-heavy diets, some seafood or occupational contact. Seafood contains harmless organic arsenic that raises the total.

An enzyme found in the liver, heart, and muscle. Often interpreted alongside ALT.

A yellow pigment made when red blood cells break down. Cleared by the liver.

Nitrogen waste from protein metabolism that your kidneys clear. A general kidney-function indicator.

Blood cadmium reflects recent and ongoing exposure to a toxic metal that accumulates in the kidneys and bone. Tobacco smoke is the most common source; shellfish, organ meats and some grains contribute.

Most calcium is in bone. Blood levels reflect parathyroid, kidney, and vitamin D function.

Mostly bicarbonate. Reflects your body's acid-base balance.

An electrolyte that helps maintain fluid balance and acid-base status.

A trace mineral essential for iron metabolism, energy production, and connective tissue health.

An enzyme released when muscle is damaged — skeletal, cardiac, or smooth muscle.

A waste product cleared by your kidneys. Levels reflect how well your kidneys are filtering.

A small protein cleared by the kidneys. An alternative kidney-function marker, especially useful when muscle mass is unusual.

A fragment from broken-down clots. Used to rule out clotting disorders like DVT or pulmonary embolism.

The processed (conjugated) form of bilirubin that the liver has prepared for excretion.

An estimate of how much blood your kidneys filter per minute, calculated from creatinine.

Estimated kidney filtration rate calculated from cystatin C. Often used to confirm creatinine-based eGFR.

A clotting protein. Also rises with inflammation as an acute-phase reactant.

A liver enzyme that's especially sensitive to bile-flow problems and alcohol-related liver stress.

Your blood sugar level. Fasting glucose is one of the primary screens for diabetes.

A standardized version of prothrombin time. Lets PT results be compared across labs and methods.

An enzyme released when cells are damaged. Non-specific — many tissues contain it.

Lead level in the blood. The CDC reference value for adults is <3.5 mcg/dL; any detectable level is a concern over time.

An enzyme made by the pancreas that helps digest fats. More specific to the pancreas than amylase.

A mineral involved in 300+ enzyme reactions, including muscle, nerve, and heart function.

Blood mercury level. Mostly reflects recent exposure (commonly from fish consumption).

A mineral that, with calcium, builds bones and teeth and supports many cellular processes.

An electrolyte essential for heart, muscle, and nerve function.

A protein with a short half-life — drops quickly when nutrition is inadequate. A sensitive nutrition marker.

How long it takes blood to clot via the extrinsic pathway. Used to monitor warfarin therapy.

An antioxidant trace mineral important for thyroid function and immune health.

A key electrolyte that controls fluid balance, blood pressure, and nerve and muscle function.

The total of albumin and globulins in your blood. A general nutrition and liver/kidney indicator.

A waste product from nucleic-acid breakdown. High levels can crystallize in joints and cause gout.

A small amount of albumin in the urine. Early sign of kidney damage from diabetes or hypertension.

A measure used to standardize other urine tests (like albumin) for hydration level.

An essential trace mineral important for immune function, wound healing, and taste/smell.

The active, unbound form of T3 — the most metabolically active thyroid hormone.

The active, unbound form of the main thyroid hormone. Confirms thyroid function alongside TSH.

An inactive form of T3 that the body produces during stress, illness, or low-calorie states.

Antibodies against thyroglobulin. Often elevated in Hashimoto's thyroiditis alongside TPO antibodies.

Antibodies against thyroid peroxidase. The most common marker of autoimmune thyroid disease.

A pituitary hormone that signals your thyroid. The most sensitive screen for thyroid problems.

A B vitamin essential for DNA synthesis and red blood cell formation.

A metabolite that builds up when cells lack usable vitamin B12. The most specific marker of functional B12 deficiency.

A fat-soluble vitamin essential for vision, immune function, and skin health.

A B vitamin essential for energy metabolism and nerve function.

A vitamin essential for nerve function and red blood cell formation. Found in animal foods.

A B vitamin needed for energy production and red blood cell formation.

A B vitamin involved in protein metabolism, neurotransmitter synthesis, and immune function.

A water-soluble antioxidant essential for collagen synthesis and immune function.

Your body's vitamin D status. Influenced by sun exposure, diet, supplements, and absorption.

A fat-soluble antioxidant that protects cell membranes from damage.

A fat-soluble vitamin essential for blood clotting and bone health.