Doctors commonly order CBC's (complete blood cell count) for many different reasons. "Diff" stands for differential. There are many different types of cells that are examined when this test is performed. Here are a few of them:
- White blood cells are counted
- A white blood cell differential is done
- Red blood cells are counted
- The amount of hemoglobin is measured
- Hematocrit is measured
- Platelets are counted
So the "diff" you are asking about is related to the white blood cell count. There are actually different types of white blood cells that are examined and this is the differential. They are neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
This is referring to a hematological test performed on your blood. CBC means complete blood count and diff. means differential. This test is very common and is used to gather information about your health status.
CBC's measure many components of the blood like the leukocyte count (white blood cells), erythrocyte count (red blood cells), hemoglobin, and hematocrit just to name a few. The differential part of the CBC evaluates other indices like the morphology of the various cells like neutrophils, lymphocytes, monocytes, eosinophils, and basophils (leukocytes) and MCV, MCH, and MCHC of the erythrocytes. Mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration respectively.
Abnormalities in the CBC or differential indicate specific and general problems that may shed light on the particular disease process.