The Complete Blood Count, or CBC, is one of the most ordered tests in medicine. In a single blood draw, it provides a wealth of information about your blood's three main components: red blood cells, white blood cells, and platelets.

Red Blood Cell Parameters

Red blood cells (RBCs) carry oxygen from your lungs to every cell in your body. The CBC measures their count, size (MCV), and hemoglobin content (MCH). Low hemoglobin or RBC count indicates anemia, while abnormal sizes can point to nutritional deficiencies or blood disorders.

White Blood Cell Count

White blood cells (WBCs) are your immune system's soldiers. A high WBC count typically indicates an active infection or inflammation. A low count may signal immune system problems or the effects of certain medications.

Platelets

Platelets are tiny cells that help your blood clot when you're injured. Too few platelets can cause excessive bleeding, while too many may increase clotting risk. Dengue fever, for example, is notorious for dangerously lowering platelet counts.