Blood work:
Two common tests to use for
monitoring HIV disease

January 2008     View PDF     En español

Viral load, disease progression and anti-HIV therapy

Higher HIV levels often relate to lower CD4 counts, more rapid declines in CD4 cell counts and more rapid disease progression. People with HIV levels over 100,000 are ten times more likely to move on to AIDS over the next five years than those with levels below 100,000. People with constant HIV levels below 10,000 seem to have a lower risk of disease progression.

Viral load tests provide information on how effective an anti-HIV regimen is. This helps people make decisions about starting, stopping and switching therapy. As stated before, effective therapy should result in a major drop in HIV levels—at least 90% or 1 log. A viral load that doesn’t change significantly after starting therapy is a sign that the therapy isn’t working. An increasing viral load while on anti-HIV therapy is a sign that the regimen is no longer working.

Viral load is only measured in the blood. Most of the time there’s a strong relationship between levels of HIV in the blood and in other body fluids like semen and vaginal fluids. However, sometimes people have undetectable levels of HIV in their blood yet have detectable levels in these other fluids. For now, there isn’t enough research to fully understand this issue.