What Is a CBC Blood Test?

A CBC (Complete Blood Count) is the most commonly ordered blood test. It measures the cells that make up your blood.

What It Measures

• Red blood cells: RBC count, hemoglobin, hematocrit, MCV, MCH, MCHC, RDW
• White blood cells: WBC count with 5-part differential
• Platelets: count and MPV

What It Screens For

• Anemia (low hemoglobin)
• Infection (high/low WBC)
• Clotting disorders (platelet abnormalities)
• Blood cancers (leukemia)
• Nutritional deficiencies (iron, B12, folate)

When Is It Ordered?

• Annual physical
• Fatigue or weakness
• Before surgery
• Monitoring medications
• Investigating infection or bleeding