Complete Blood Count (CBC)
Definition
A group of tests that measures the number and size of the cells in the blood. Red blood cells (erythrocytes), white blood cells (leukocytes), platelets, hemoglobin, hematocrit and mean corpuscular volume (MCV) are evaluated in this group.
Purpose
Used as part of routine check-ups and for monitoring conditions that affect blood cell counts: infections, anemia, immune system disorders and blood cancers. It helps in the diagnosis of blood disorders.
Results
Low red blood cell / hemoglobin / hematocrit values may point to dehydration, anemia or heart disease. A low white blood cell count may suggest autoimmune diseases or bone marrow disorders; a high white blood cell count may suggest infection or a drug reaction.
Normal Values
Laboratory-specific, refer to the reference range on your report; ranges vary by age, sex and the instrument used.
Current literature is debating whether sex-specific hemoglobin reference ranges may be flawed and whether relying on a hemoglobin threshold alone may lead to missed diagnoses in menstruating women.
Risks and Limitations
The risk of the blood draw is very low; there may be slight pain or bruising at the needle site, which usually resolves quickly. The main limitation of the test lies in interpretation: diet, level of physical activity and medications used can affect the results. It does not make a diagnosis on its own; it must be evaluated together with the medical history and symptoms.