A Complete Blood Count (CBC), also called a full blood count, is the most commonly ordered blood test. It counts and measures your red blood cells (which carry oxygen), white blood cells (which fight infection) and platelets (which help blood clot).
Why is it done?
Doctors order it at routine check-ups and whenever someone has tiredness, fever, infections, bruising, bleeding or weight loss. It is also used to monitor many treatments.
How to prepare
No fasting is needed. Tell the lab if you have recently had a fever, heavy exercise or a blood transfusion.
How to read your results
Start with hemoglobin: low means anemia. Then look at MCV: small cells suggest iron deficiency or thalassemia trait; large cells suggest B12 or folate deficiency. The white cell count and its differential show infection or allergy, and the platelet count shows clotting ability.
Tests in this panel and their normal ranges
| Test | Normal range (adults) |
|---|---|
| Hemoglobin (Hb) | Men 13.5–17.5 g/dL (135–175 g/L) Women 12–15.5 g/dL (120–155 g/L) |
| White Blood Cell Count (WBC / TLC) | 4–11 ×10⁹/L (4–11 ×10³/µL) |
| Platelet Count | 150–400 ×10⁹/L (150–400 ×10³/µL) |
| Red Blood Cell Count (RBC) | Men 4.5–5.9 ×10¹²/L (4.5–5.9 ×10⁶/µL) Women 4–5.2 ×10¹²/L (4–5.2 ×10⁶/µL) |
| Hematocrit (HCT / PCV) | Men 41.5–50.4% Women 35.9–44.6% |
| MCV (Mean Corpuscular Volume) | 80–100 fL |
| MCH (Mean Corpuscular Hemoglobin) | 27–33 pg |
| MCHC | 32–36 g/dL (320–360 g/L) |
| RDW (Red Cell Distribution Width) | 11.5–14.5% |
| MPV (Mean Platelet Volume) | 7.5–12.5 fL |
| Neutrophils | 40–75% |
| Absolute Neutrophil Count (ANC) | 1.8–7.7 ×10⁹/L |
| Lymphocytes | 20–45% |
| Monocytes | 2–10% |
| Eosinophils | 1–6% |
| Basophils | Up to 1% |
| ESR (Erythrocyte Sedimentation Rate) | Men Up to 15 mm/hr Women Up to 20 mm/hr |
Ranges vary slightly between laboratories. The range printed on your own report is the one to go by.
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This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.