Complete Blood Count

Function

The Complete Blood Count (CBC) is one of the most common and essential diagnostic tests in medicine. It evaluates the three major types of cells in the blood: Red Blood Cells (RBCs), White Blood Cells (WBCs), and Platelets. Each component provides vital information about the body's ability to transport oxygen, fight infection, and stop bleeding.

Why it is Ordered

A CBC is often part of a routine check-up but is also used to diagnose symptoms like fatigue, bruising, or fever. It is critical for monitoring patients undergoing treatments like chemotherapy, which can suppress bone marrow function.

Associated Conditions

• Anemia: Characterized by low Hemoglobin or RBC count, often causing exhaustion.
• Infection: Elevated WBC counts (leukocytosis) usually signal an immune response to bacteria or viruses.
• Leukemia/Lymphoma: Significant abnormalities in WBC types and counts can indicate blood cancers.
• Thrombocytopenia: A low platelet count that puts a patient at risk for internal bleeding.

Interpreting Sub-components

A CBC includes the 'Differential,' which breaks down WBCs into neutrophils, lymphocytes, monocytes, eosinophils, and basophils. It also includes RBC indices (MCV, MCH, MCHC) which help classify the type of anemia (e.g., iron deficiency vs. B12 deficiency).