Common lab markers, explained in plain language

A1C

Also called: Hemoglobin A1c, HbA1c, Glycated hemoglobin

A1C is a blood test that reflects average blood glucose over roughly the prior two to three months.

Glucose

Also called: Blood sugar, Serum glucose, Plasma glucose

Glucose measures the concentration of sugar in the blood at the time the sample was taken.

LDL cholesterol

Also called: LDL-C, Low-density lipoprotein cholesterol

LDL cholesterol is one component of a lipid panel and is often discussed in conversations about cardiovascular risk.

HDL cholesterol

Also called: HDL-C, High-density lipoprotein cholesterol

HDL cholesterol is another lipid-panel marker commonly reviewed alongside LDL and triglycerides.

Triglycerides

Also called: TG, Trigs

Triglycerides are a type of fat in the blood, typically reported as part of a lipid panel.

Total cholesterol

Also called: Cholesterol, Total

Total cholesterol adds up LDL, HDL, and a portion of triglycerides on a lipid panel.

Non-HDL cholesterol

Also called: Non-HDL-C

Non-HDL cholesterol is total cholesterol minus HDL cholesterol.

Creatinine

Also called: Serum creatinine

Creatinine is a waste product measured in blood and often used when assessing kidney-related lab context.

eGFR

Also called: Estimated glomerular filtration rate

eGFR is an estimate of kidney filtration rate derived from creatinine (and sometimes other inputs) using a laboratory equation.

BUN

Also called: Blood urea nitrogen, Urea nitrogen

BUN measures a waste product from protein breakdown, often reported with creatinine.

ALT

Also called: Alanine aminotransferase, SGPT

ALT is an enzyme often included in liver-related blood panels.

AST

Also called: Aspartate aminotransferase, SGOT

AST is an enzyme measured on many metabolic or liver panels and reviewed alongside ALT.

Albumin

Also called: Serum albumin

Albumin is a protein made by the liver and is often included on metabolic and liver panels.

Alkaline phosphatase

Also called: ALP, Alk Phos

Alkaline phosphatase is an enzyme found in liver, bone, and other tissues.

Total protein

Also called: Serum total protein

Total protein adds up all proteins in the blood, mainly albumin and globulins.

Bilirubin

Also called: Total bilirubin

Bilirubin is a byproduct of red blood cell breakdown, processed by the liver.

Direct bilirubin

Also called: Conjugated bilirubin, Bilirubin, Direct

Direct bilirubin is the form of bilirubin that has already been processed by the liver.

TSH

Also called: Thyroid-stimulating hormone

TSH is a pituitary hormone measured when clinicians evaluate thyroid-related lab context.

Free T4

Also called: Free thyroxine, FT4

Free T4 measures the unbound, active portion of thyroxine, a thyroid hormone.

Vitamin D

Also called: 25-hydroxyvitamin D, 25(OH)D

Vitamin D blood tests usually report 25-hydroxyvitamin D, a common circulating form used in lab panels.

Vitamin B12

Also called: B12, Cobalamin

Vitamin B12 is measured to look at levels of this vitamin, often alongside folate.

Folate

Also called: Vitamin B9, Folic acid

Folate is a B vitamin sometimes measured alongside vitamin B12.

Iron

Also called: Serum iron

Serum iron measures the amount of iron currently circulating in the blood.

Ferritin

Also called: Serum ferritin

Ferritin reflects the body's stored iron and is often ordered alongside other iron studies.

TIBC

Also called: Total iron-binding capacity

TIBC estimates the blood's capacity to carry iron, using transferrin as the main carrier.

Transferrin saturation

Also called: Iron saturation, TSAT

Transferrin saturation is a calculated percentage showing how much of the iron-carrying capacity is in use.

Calcium

Also called: Serum calcium, Total calcium

Calcium supports bone, muscle, and nerve function and is reported on most metabolic panels.

Sodium

Also called: Na, Serum sodium

Sodium is an electrolyte that helps regulate fluid balance and is part of most metabolic panels.

Potassium

Also called: K, Serum potassium

Potassium is an electrolyte important for muscle and nerve function, included on metabolic panels.

Chloride

Also called: Cl, Serum chloride

Chloride is an electrolyte that helps maintain fluid balance and is reported on metabolic panels.

CO2 (bicarbonate)

Also called: Carbon dioxide, Bicarbonate, HCO3, CO2 total, CO2, Total CO2

This test estimates bicarbonate, part of the body's acid-base balance, and is part of metabolic panels.

White blood cell count

Also called: WBC, Leukocyte count

WBC count is part of a complete blood count (CBC) and reflects the number of white blood cells in a sample.

Red blood cell count

Also called: RBC, Erythrocyte count

RBC count is part of a complete blood count (CBC) and reflects how many red blood cells are in a sample.

Hemoglobin

Also called: Hgb, Hb

Hemoglobin is the protein in red blood cells that carries oxygen, measured on a CBC.

Hematocrit

Also called: Hct, Packed cell volume

Hematocrit is the percentage of blood volume made up of red blood cells, part of a CBC.

MCV

Also called: Mean corpuscular volume

MCV describes the average size of red blood cells and is one of the CBC red-cell indices.

MCH

Also called: Mean corpuscular hemoglobin

MCH estimates the average amount of hemoglobin inside each red blood cell.

MCHC

Also called: Mean corpuscular hemoglobin concentration

MCHC estimates the concentration of hemoglobin within red blood cells.

RDW

Also called: Red cell distribution width

RDW describes how much variation there is in the size of red blood cells.

Platelets

Also called: Platelet count, Thrombocytes

Platelets help blood clot and are counted as part of a complete blood count.

hs-CRP

Also called: High-sensitivity C-reactive protein

hs-CRP is a sensitive measurement of C-reactive protein, a general marker your body produces during inflammation.

NT-proBNP

Also called: N-terminal pro-B-type natriuretic peptide, BNP precursor

NT-proBNP is a blood marker that can reflect strain on the heart and is interpreted in clinical context.

PT / INR

Also called: Prothrombin time, INR, PT, Prothrombin time / INR

PT and INR are measurements related to how quickly blood forms a clot.

Testosterone

Also called: Total testosterone

Total testosterone measures this hormone's overall concentration in the blood.

Free testosterone

Also called: Free T

Free testosterone measures the unbound, biologically active portion of testosterone.