CBC
The complete blood count (CBC) measures the cellular components of blood: red blood cells, white blood cells, and platelets. It includes hemoglobin and hematocrit (oxygen-carrying capacity), WBC (immune cell count), the white cell differential (neutrophils, lymphocytes, monocytes, eosinophils), platelet count (hemostasis), and red cell indices (MCV, MCH, MCHC, RDW) that describe red cell size, hemoglobin content, and size variability. The CBC is the most commonly ordered blood test panel.
Also listed under Hematology .
Frequently Asked Questions
What does a CBC measure?
A CBC quantifies the three main cell lines in blood: red blood cells (measured by hemoglobin, hematocrit, and RBC count), white blood cells (total WBC count), and platelets. It also includes red cell indices (MCV, MCH, MCHC, RDW) that describe cell size and hemoglobin content.
Why are the CBC reference ranges split by sex and age?
Red blood cell parameters differ substantially between males and females due to testosterone effects on erythropoiesis and menstrual iron losses. Both red and white cell parameters shift with age as bone marrow function, kidney erythropoietin production, and chronic disease prevalence change.
Does this panel include the white blood cell differential?
Yes. The total WBC count is broken down into its main components, each with its own page: neutrophils, lymphocytes, monocytes, and eosinophils. These are reported as absolute counts in 1000 cells/uL, consistent with the total WBC count. Basophils are not included because their absolute count in this source is reported at a resolution too coarse to describe a meaningful population distribution.