Measure how well HIV drugs are working

HIV drugs work by preventing the virus from reproducing. When a regimen is working, the viral load usually goes down within weeks of starting. If viral load goes up while using HIV drugs, you and your doctor should take another viral load measurement, and look closer to see if there are any problems with adherence or resistance, and determine whether you may need to change drugs in your regimen.

One goal of HIV treatment is to keep viral load levels as low as possible for as long as possible. With effective HIV treatment regimens, viral load can be reduced to levels that cannot be detected by lab tests. With most viral load tests this is below 50 copies per mL of blood.

Even if your viral load is undetectable, HIV is still in your body in very small quantities, in places like the lymph nodes, spleen, and genital tract. If you stop taking your HIV drugs, the virus usually starts multiplying and eventually, the viral load increases.