Glossary of lab terms for GLP-1 therapy: abbreviations, units and conversions

Definitions are kept to what you need to read a report and follow the pages on this site. Where a term has its own page, the link goes there.

Tests and abbreviations

A1c (HbA1c, glycated hemoglobin). The percentage of hemoglobin with glucose attached; reflects average glucose over about three months. Page.

ALP (alkaline phosphatase). Enzyme from bile ducts and bone. Rises when bile flow is blocked. Liver enzymes.

ALT (alanine aminotransferase, SGPT). Liver cell enzyme; the most liver-specific of the panel. Liver enzymes.

AST (aspartate aminotransferase, SGOT). Enzyme from liver, muscle and heart. Liver enzymes.

BMP (basic metabolic panel). The first eight tests of the CMP: glucose, calcium, sodium, potassium, chloride, CO2, BUN, creatinine.

BUN (blood urea nitrogen). Waste product cleared by the kidney; rises with reduced filtration and with dehydration. Kidney.

Calcitonin. Hormone from thyroid C cells; used as a tumor marker for medullary thyroid carcinoma. Page.

CBC (complete blood count). Red cells, white cells, platelets and the red cell indices. Page.

CMP (comprehensive metabolic panel). Fourteen tests covering glucose, kidney, electrolytes, liver and proteins. Page.

CO2 (bicarbonate, total CO2). The blood's main buffer; an acid-base measure, not a lung test. Electrolytes.

Creatinine. Muscle waste product cleared by the kidney; used to calculate eGFR. Falls as muscle mass falls. Kidney.

eGFR (estimated glomerular filtration rate). Kidney filtration estimated from creatinine (or cystatin C), age and sex; reported in mL/min/1.73 m2. Kidney.

Ferritin. Iron storage protein; the blood level tracks iron stores but also rises with inflammation. Iron.

FPG (fasting plasma glucose). Glucose after at least eight hours without calories. Page.

hCG (human chorionic gonadotropin). Pregnancy hormone; qualitative tests give yes or no, quantitative tests give a number. Pregnancy test.

HDL, LDL. High-density and low-density lipoprotein cholesterol. Lipid panel.

Lipase, amylase. Pancreatic enzymes; both rise on average on GLP-1 therapy, and the labels say an isolated rise has unknown significance. Page.

MCV (mean corpuscular volume). Average red cell size; small in iron deficiency, large in B12 or folate deficiency. CBC.

MMA (methylmalonic acid). Rises when cells lack usable B12; confirms a deficiency. B12.

TIBC (total iron binding capacity), transferrin saturation. Iron transport capacity and how full it is. Iron.

TSH (thyroid-stimulating hormone). Pituitary signal to the thyroid; the screening test for thyroid function. Does not test C cells. Page.

UACR (urine albumin-to-creatinine ratio). Spot-urine measure of albumin leakage, used with eGFR to stage kidney disease. Kidney.

25-hydroxyvitamin D (25(OH)D). The storage form of vitamin D measured in blood. Page.

Conditions and label phrases

Cholelithiasis, cholecystitis, cholecystectomy. Gallstones, gallbladder inflammation, gallbladder removal. Gallbladder.

Contraindication. A situation in which the label says the drug should not be used. For semaglutide and tirzepatide: personal or family history of MTC, MEN 2, or a serious hypersensitivity reaction to the drug.

Insulin secretagogue. A drug that makes the pancreas release insulin, chiefly sulfonylureas (glipizide, glimepiride, glyburide) and meglitinides. Named in the labels' hypoglycemia warning.

MASH (metabolic dysfunction-associated steatohepatitis), formerly NASH. Fatty liver with inflammation; Wegovy carries an indication for the noncirrhotic form with F2 to F3 fibrosis. MASLD is the broader term for fatty liver disease.

MEN 2 (Multiple Endocrine Neoplasia syndrome type 2). Inherited syndrome causing medullary thyroid carcinoma; a contraindication.

MTC (medullary thyroid carcinoma). Rare thyroid cancer of the C cells; the subject of the boxed warning.

Prediabetes. A1c 5.7% to 6.4%, or fasting glucose 100 to 125 mg/dL, per the ADA.

Volume depletion. The labels' phrase for loss of body fluid (from vomiting, diarrhea, poor intake) that can reduce kidney perfusion; the trigger for their renal function instruction.

Kidney disease categories (KDIGO 2024)

G1 eGFR 90 or higher. G2 60 to 89. G3a 45 to 59. G3b 30 to 44. G4 15 to 29. G5 under 15. Albuminuria: A1 UACR under 30 mg/g, A2 30 to 300, A3 over 300. CKD requires an abnormality persisting more than three months.

Units and conversions

A1c has two scales rather than a conversion factor: the NGSP percentage used in the US and the IFCC mmol/mol used in some countries. 5.7% is 39 mmol/mol; 6.5% is 48 mmol/mol; 7.0% is 53 mmol/mol.

Report vocabulary

Reference interval. The laboratory's usual range for that test, typically the central 95% of a healthy reference population. Varies by lab. How to read a report.

Flag (H, L, critical). A marker that a result is outside the reference interval; a comparison, not a diagnosis.

Hemolyzed, lipemic, icteric. Sample quality comments: red cells broke, the sample was fatty, or it was jaundiced. Each interferes with certain tests.

Delta check. Comparison of a result with the same person's previous result.

Fasting. No calories for a stated period, usually 8 to 12 hours; water is allowed.

For dosing vocabulary (units, concentration, titration), the FormBlends calculators site has its own glossary.