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HIV & AIDS Health Center

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Screening Tests for HIV Diagnosis and Treatment

HIV Screening Tests After Diagnosis continued...

A normal CD4 count is more than 500 cells per cubic millimeter (mm3) of blood. The lower the CD4 count, the less your immune system is functioning, and the more likely you are to get infections. Your doctor will probably start treatment by the time a CD4 count is under 500 cells/mm3. If your CD4 count drops to below 200/mm3, you are said to have full-blown AIDS.

Viral load test. A viral load test measures how much of the HIV virus is in the blood. You want to have a low viral load because it means treatment is helping to control the virus. If your treatment is working effectively, the viral load should drop to an undetectable level in your blood.

You'll have your viral load tested two to four weeks after starting treatment, then every four to eight weeks until the viral load is no longer detectable. An undetectable viral load doesn't mean you're not infected -- just that the amount of HIV in the blood is too low for the test to pick up.

Continue to have your viral load tested every three or four months to be sure antiviral medications are still working.

Drug resistance testing. Your doctor will also test you to make sure the strain of HIV you have isn't resistant to any medications. Sometimes HIV will change (mutate) into a form that certain drugs can't treat.

Other screening tests may be done prior to starting certain treatment regimens and to monitor drug levels.

Your doctor will probably also order several other tests to monitor your health and screen for diseases that are more likely in people with HIV. These tests might include:

It's important to see your doctor for all scheduled HIV tests. These tests can help your doctor plan your HIV treatment and monitor you for other conditions so that you can stay as healthy as possible.

WebMD Medical Reference

Reviewed by Kimball Johnson, MD on December 11, 2013
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