CD4 cells are white blood cells called T lymphocytes or T cells that fight infection and play an important role in immune system function. They are made in the thymus gland and they circulate throughout the body in the blood and lymphatic system. CD4 tests measure the number of these cells in the blood and, in conjunction with an HIV viral load test, help assess the status of the immune system in a person who has been diagnosed…
Why Get Tested?
Most often, this test is done to measure the strength of your immune system if you have been diagnosed with human immunodeficiency virus (HIV) infection and to monitor treatment; occasionally, it may be used with other conditions.
When To Get Tested?When you are first diagnosed with HIV infection to get a baseline assessment of your immune system; about every 3 to 6 months after starting antiretroviral therapy (ART) to check whether you are responding to treatment; if you have responded well to treatment, you may then be tested every 6 to 12 months.
A blood sample drawn from a vein in your arm