White Blood Cell Count with Differential by Manual Count (Qualitative)

What This Test Measures

A manual differential count examines five main types of white blood cells: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Each cell type serves a distinct role in your body’s defense against illness. The manual method involves counting cells under a microscope by a trained technician, providing detailed qualitative results rather than precise numeric values.

Why It’s Done

Doctors may order this test to diagnose infections (like bacterial or viral), evaluate immune disorders, check for blood disorders (such as leukemia), or monitor conditions like allergies or autoimmune diseases. It’s also useful when other blood tests show abnormal white cell counts.

Sample Collection and Preparation

A small blood sample is drawn from your arm, typically using a needle. The sample is then processed and examined under a microscope by a lab technician. Unlike automated tests, this method requires careful visual inspection to count and categorize each white blood cell type.

Interpreting Results

Results are qualitative (descriptive) rather than numeric, focusing on the relative proportions of each cell type. For example, a high percentage of neutrophils might suggest an infection, while a high percentage of lymphocytes could indicate a viral infection or immune response. Your doctor will interpret these findings in the context of your overall health and symptoms.