Version July 2025
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How do doctors monitor people with HIV? —
Doctors monitor people with HIV by doing regular exams, talking to them, and doing tests. There are 2 especially important tests for keeping track of whether HIV treatment is working. These are called the "viral load test" and the "CD4 cell count."
What is viral load? —
This is the amount of virus in the blood. If you have HIV, it's important to have your viral load tested regularly. It helps your doctors check on your infection and shows whether your treatment is working.
The goal of treatment is to get your viral load below "detectable levels." That means there is so little virus in your blood that the test cannot even pick it up.
What are CD4 cell counts? —
HIV attacks and destroys the cells in the body that fight infection. It especially likes to kill a type of cell called "CD4+ T" cells. These are often called "CD4 cells" or "T cells" for short.
The number of CD4 cells you have has a lot to do with how well your body can fight infection. In general, people who have CD4 cell counts below 200 have a hard time fighting infections. They can get "opportunistic" infections. These are caused by germs that healthy people's bodies can usually fight off. In people with HIV, though, these germs can cause infection.
If your CD4 count gets too low, your doctor will probably want to give you medicines to keep you from getting opportunistic infections. For example, if your CD4 count falls below 200, your doctor might give you antibiotics to prevent a lung infection called "PCP pneumonia." When your CD4 counts get back up over 200, you can usually stop the antibiotics after a few months.
How often should I have viral load and CD4 tests? —
It depends mostly on your CD4 count and how your treatment is going.
Some people need to be tested every 2 to 8 weeks. This might include people who:
●Were recently diagnosed
●Recently started treatment
●Recently changed treatment
People whose HIV seems to be under control and who are not changing medicines or doses might go 6 months or longer between testing. Some people might not need CD4 tests at all.
It is very important to follow your doctor's instructions about getting tested. The results of your viral load tests tell your doctor whether your HIV treatment is helping. The results of your CD4 tests tell your doctor how well your immune system is working.
Can anything besides HIV affect viral load and CD4 test results? —
Your viral load is mostly affected by your HIV treatment. If your treatment is working right, your viral load should go down below the level the test can even detect.
Sometimes, tests show something called a "viral blip." This is when the viral load temporarily increases to a low level, usually between 20 and 200. If you are taking your HIV medicines as prescribed, a viral blip usually does not mean there is a problem. But talk to your doctor if this happens. They will check to see if anything might be affecting how well your medicines are working, for example, foods or other medicines you take.
CD4 counts can go down because of a lot of things, including:
●Infections (other than HIV)
●Alcohol misuse
●Pregnancy
●Liver disease
Patient education: HIV and AIDS (The Basics)
Patient education: HIV blood test (The Basics)
Patient education: Starting treatment for HIV (The Basics)
Patient education: Vaccines for adults with HIV (The Basics)
Patient education: Preventing HIV after a possible exposure (The Basics)
Patient education: Exposure to HIV or hepatitis through blood or body fluids (The Basics)
Patient education: Testing for HIV (Beyond the Basics)
Patient education: Symptoms of HIV (Beyond the Basics)
Patient education: Initial treatment of HIV (Beyond the Basics)
Patient education: Tips for taking HIV medications by mouth (Beyond the Basics)
Patient education: HIV and pregnancy (Beyond the Basics)
