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Techniques and interpretation of HIV-1 RNA quantitation

Angela M Caliendo, MD, PhD
Section Editor
John G Bartlett, MD
Deputy Editor
Jennifer Mitty, MD, MPH


Human immunodeficiency virus type 1 (HIV-1) RNA can be measured using qualitative or quantitative techniques. Qualitative testing (commonly referred to as nucleic acid testing or NAT) is used as a screening test to identify HIV infected individuals, such as screening possible blood donors. Quantification of HIV-RNA (viral load measurements) can be used as a diagnostic test in certain situations; however, the HIV viral load is primarily used for management/monitoring of HIV-1 infected individuals.

This topic will address the laboratory methods for quantitation of HIV-1 RNA and the use of viral load for clinical management. Information on nucleic acid, HIV-2 RNA, and CD-4 cell count testing is found elsewhere. (See "Blood donor screening: Laboratory testing", section on 'HIV-1 and HIV-2' and "Clinical manifestations and diagnosis of HIV-2 infection", section on 'Testing for HIV-2 infection' and "Techniques and interpretation of measurement of the CD4 cell count in HIV-infected patients".)


Studies have shown HIV-1 RNA levels to be a predictor of the time to progression to acquired immunodeficiency syndrome (AIDS) and death that is independent of CD4 cell counts [1-6]. Viral load measurements are also useful in determining when to initiate antiretroviral therapy, and in monitoring the response to such therapy [7-11]. (See "Selecting antiretroviral regimens for the treatment-naïve HIV-infected patient" and "Patient monitoring during HIV antiretroviral therapy".)

In specific situations (neonatal infection and acute infection), HIV-1 RNA levels also may be useful in establishing the diagnosis of HIV infection, but HIV antibody tests are primarily used for this purpose.


There are four commercial assays that have been approved by the United States Food and Drug Administration (FDA) to quantify HIV-1 RNA from plasma samples:


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Literature review current through: Sep 2015. | This topic last updated: Jan 30, 2014.
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