Misdiagnosis of HIV infection by HIV-1 plasma viral load testing: a case series.

BACKGROUND The availability of sensitive assays for plasma HIV viral load and the trend toward earlier and more aggressive treatment of HIV infection has led to the inappropriate use of these assays as primary tools for the diagnosis of acute HIV infection. OBJECTIVE To describe limitations in the use of plasma viral load testing for the diagnosis of HIV infection. DESIGN Case series. SETTING Academic medical centers in Providence, Rhode Island, and Worcester, Massachusetts. PATIENTS Three persons in whom HIV infection was falsely diagnosed by plasma viral load testing. MEASUREMENTS Laboratory measures and clinical outcomes. RESULTS Two cases of false-positive results obtained by using branched-chain DNA plasma viral load assays and one case of a false-positive result obtained by using reverse transcriptase-polymerase chain reaction plasma viral load assay are reported. All three plasma viral load tests yielded positive results with low values (1254 copies/mL, 1574 copies/mL, and 1300 copies/mL). Infection with HIV was initially diagnosed in all three patients, but each patient subsequently tested negative by HIV-1 enzyme-linked immunosorbent assay and repeated plasma viral load testing. CONCLUSION Physicians should exercise caution when using plasma viral load assays to detect primary HIV infection, particularly when the pretest probability of infection is low.