Lymphocyte Count (Manual Differential Blood Count)

Why This Test May Be Ordered

Your healthcare provider may order this test to check for infections, immune system conditions, or other health issues. It could be used if you have symptoms like frequent infections, fatigue, or unexplained weight loss. It may also be part of routine blood work or monitoring for certain diseases.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast before the test if it’s part of a larger blood draw, but this is not always required for just the lymphocyte count. Bring any medications or questions to your appointment.

How the Test Is Performed

A healthcare professional will draw blood from a vein, usually in your arm, using a small needle. The blood will be sent to a lab where it is examined under a microscope to count the lymphocytes and other white blood cells.

What the Results Mean

Results are typically reported as a count of lymphocytes per microliter (µL) of blood. A lower than expected count may indicate immune suppression, infection, or certain medical conditions. A higher count might suggest an overactive immune response or other health concerns. Always discuss your results with your healthcare provider.