Patient Guide

Blood Tests A to Z: Common Lab Tests Explained

Name: Blood Tests A to Z: Complete Guide to Common Lab Tests
Creator: Suman Konda
Published: 2026-07-05

This A–Z guide covers the most commonly ordered blood tests. Use it to quickly look up what any blood test measures and what your result means.

Last updated: 01 August 2026 · How we check our content

A

Test	Normal Range	What it measures
Albumin	3.5–5.0 g/dL	Main blood protein; low in liver disease, malnutrition, kidney disease
ALP (Alkaline Phosphatase)	44–147 U/L	Liver/bile duct or bone disease
ALT (Alanine aminotransferase)	7–56 U/L	Liver cell damage: most specific liver enzyme
ANA	Negative / <1:40	Autoimmune screening: lupus, Sjögren's, scleroderma
AST (Aspartate aminotransferase)	10–40 U/L	Liver and muscle damage

B

Test	Normal Range	What it measures
Bilirubin (total)	0.1–1.2 mg/dL	Jaundice: liver, bile duct or haemolysis
BNP / NT-proBNP	BNP <100 pg/mL	Heart failure: stretching of heart chambers
Blood urea / BUN	7–20 mg/dL	Kidney function and hydration status

C

Test	Normal Range	What it measures
Calcium	8.5–10.5 mg/dL	Bone health, parathyroid, kidney, malignancy
CBC / FBC	See individual parameters	Red cells, white cells, platelets: full picture
Cholesterol (LDL)	<100 mg/dL optimal	Heart disease risk: main statin target
CK (Creatine Kinase)	55–170 U/L	Muscle damage: myopathy, rhabdomyolysis
Creatinine	Men: 0.74–1.35 mg/dL; Women: 0.59–1.04 mg/dL	Kidney waste product: rises as kidneys fail
CRP	<10 mg/L	Inflammation: rises quickly with infection or flare

D – G

Test	Normal Range	What it measures
D-Dimer	<0.5 mg/L	Blood clot activity: DVT, PE screening
ESR	Men: <15 mm/hr; Women: <20 mm/hr	Chronic inflammation: slower than CRP
Ferritin	Men: 24–336 ng/mL; Women: 11–307 ng/mL	Iron stores: most sensitive iron deficiency marker
GGT (Gamma-GT)	Men: <71 U/L; Women: <42 U/L	Liver/bile duct + alcohol marker
Glucose (fasting)	70–100 mg/dL	Diabetes screening and monitoring

H – M

Test	Normal Range	What it measures
HbA1c	<5.7% normal; 5.7–6.4% pre-diabetes; ≥6.5% diabetes	Average blood sugar over 3 months
Haemoglobin	Men: 13.5–17.5; Women: 12.0–15.5 g/dL	Oxygen carrier: low = anaemia
HDL Cholesterol	Men: >40 mg/dL; Women: >50 mg/dL	"Good" cholesterol: protective against heart disease
INR	0.8–1.2 (2.0–3.0 on warfarin)	Blood clotting time: liver function and warfarin monitoring
LDH	140–280 U/L	Cell damage: haemolysis, heart attack, cancer
LFT panel	See individual tests	Liver health: enzymes + synthetic function
Magnesium	1.7–2.2 mg/dL	Electrolyte: arrhythmia risk when low

P – Z

Test	Normal Range	What it measures
Phosphorus	2.5–4.5 mg/dL	Bone mineral: rises in kidney disease
Platelets	150,000–400,000/µL	Clotting cells: low = bleeding risk; high = clot risk
Potassium	3.5–5.0 mEq/L	Electrolyte: heart rhythm critical; high dangerous
PSA	<4.0 ng/mL	Prostate cancer screening in men
Sodium	136–145 mEq/L	Fluid balance: hyponatraemia common in elderly
Testosterone (total, men)	300–1,000 ng/dL	Male hormone: low causes fatigue, reduced libido
Troponin	<0.04 ng/mL (varies by lab)	Heart muscle damage: definitive heart attack test
TSH	0.4–4.0 mIU/L	Thyroid function: low in hyperthyroid; high in hypothyroid
Uric Acid	Men: 3.5–7.2 mg/dL; Women: 2.6–6.0 mg/dL	Gout: crystals in joints when high
Vitamin B12	200–900 pg/mL	Nerve and red cell health
Vitamin D (25-OH)	30–100 ng/mL	Bone and immune health
WBC (white count)	4,500–11,000/µL	Immune cells: high = infection; low = marrow/viral
Zinc	70–120 mcg/dL	Immune function, wound healing, taste

Blood Tests A to Z: Common Lab Tests Explained

A