Page 19 - HIV/AIDS Guidelines

Laboratory Testing

Laboratory Testing for Initial Assessment and Monitoring While on Antiretroviral Therapy
(Last updated January 10, 2011; last reviewed January 10, 2011)
A number of laboratory tests are important for initial evaluation of HIV-infected patients upon entry into
care, during follow-up if antiretroviral therapy (ART) has not been initiated, and prior to and after initiation
or modification of therapy to assess virologic and immunologic efficacy of ART and to monitor for
laboratory abnormalities that may be associated with antiretroviral (ARV) drugs. Table 3 outlines the Panel’s
recommendations for the frequency of testing. As noted in the table, some of the tests may be repeated more
frequently if clinically indicated.

Two surrogate markers are used routinely to assess the immune function and level of HIV viremia: CD4 T-cell
count (CD4 count) and plasma HIV RNA (viral load). Resistance testing should be used to guide selection of
an ARV regimen in both ART-naive and ART-experienced patients; a viral tropism assay should be performed
prior to initiation of a CCR5 antagonist; and HLA-B*5701 testing should be performed prior to initiation of
abacavir (ABC). The rationale and utility of these laboratory tests are discussed below.

Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents C-1

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