CD4 and CD8
Also known as: T4 count; T-helper cells; T-suppressor cells; Cytotoxic T-cells
Formal name: CD4 lymphocyte count; CD8 lymphocyte count; CD4/CD8 ratio; CD4 percent
Related tests: HIV antibody; p24 antigen test; HIV viral load; HIV genotypic resistance testing; HIV phenotypic resistance testing
At a Glance
Why Get Tested?
Most often, this test is done to measure the strength of your immune system if you have been diagnosed with HIV infection; occasionally, it may be used with other conditions (see FAQ #4).
When to Get Tested?
If you’ve been diagnosed with HIV, soon after you are first diagnosed to get a baseline assessment of your immune system; 2-8 weeks after starting anti-HIV therapy and then every three to four months if you continue therapy
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None
