White Blood Cell Differential Count (Manual Count)

What This Test Measures

A white blood cell differential count breaks down your blood into five main types of white blood cells: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Each type plays a unique role in fighting infections or responding to inflammation. The manual count involves examining blood smears under a microscope to count these cells precisely.

Why It’s Done

Doctors may order this test to diagnose or monitor conditions like infections (e.g., bacterial vs. viral), autoimmune diseases, leukemia, or reactions to medications. It also helps track how well treatments are working or if your immune system is functioning normally.

Sample Preparation and Process

Your blood sample is drawn and spread thinly on a microscope slide. A trained lab technician then examines the slide under a microscope, counting each type of white blood cell in a specific area of the smear. This manual method provides detailed results that may differ slightly from automated counts.

When Results Might Be Abnormal

Results may show elevated or low counts of specific white blood cells, which can signal underlying health concerns. For example, high neutrophil counts might indicate infection, while high eosinophil counts could suggest allergies or parasitic infections. Always discuss any deviations with your healthcare provider.