Impact of viral load testing on patient care.

Quantitative human immunodeficiency virus (HIV) type 1 RNA tests have been essential tools in increasing our understanding of HIV pathogenesis and antiretroviral therapy. The plasma HIV RNA level is among the most powerful predictive tests in modern medicine for disease progression and has rapidly become the standard of practice for guiding clinicians in initiating, monitoring, and changing antiretroviral therapy. In this article the scientific rationale and clinical indications for viral load testing in HIV infection are reviewed.