Basophil Blood Count (with Differential)

What Is a Basophil?

Basophils are a rare but important type of white blood cell. They release chemicals like histamine and heparin, which play roles in allergic reactions and inflammation. While they’re less common than other white blood cells (like neutrophils or lymphocytes), they’re essential for immune defense.

Why Might Your Basophil Count Be Tested?

Your doctor may order this test if you have symptoms like persistent itching, skin rashes, or swelling that suggest allergies. It can also help diagnose conditions like chronic myeloproliferative disorders (e.g., CML) or certain infections.

How Is This Test Performed?

A small sample of your blood is drawn, typically from your arm, and analyzed under a microscope or automated machine to count basophils among other white blood cells. The result is expressed as a percentage or absolute count (cells per microliter).

What Do Results Mean?

Results are compared to a reference range specific to your lab, but basophils are usually very low in healthy people (often <0.005% of total white blood cells). Elevated basophils may signal allergies, infections, or blood disorders, while very low levels could indicate immune suppression or other conditions.