Routine rapid HIV test is negative in 13% of newly diagnosed HIV infections in MSM at risk for STI
Background: At the Outpatient STI Clinic of the Health Services Amsterdam all MSM are routinely offered HIV testing (opting-out) using a rapid HIV antibody test. To prevent further transmission of HIV, it is important to identify all acute – and highly infectious – infections. The objective of the present study is to examine the proportion of acute HIV infections circulating among the MSM that are not identified by this routine rapid test procedure.
Methods: MSM except those already known to be HIV infected were routinely tested using the rapid HIV test (Abbott Determine). Positive results are confirmed with western Blot (WB, INNO-LIA HIV I/II score). Serum samples of 479 rapid testers were also tested with the HIV antibody/antigen test (Abbott Axsym System). All positive and dubious combo-results were confirmed with WB. An additional p24-antigen test was done only after a negative HIV-blot or a dubious HIV-combo result.
Results: 22 out of 479 MSM with a unknown of previous HIV negative test had an HIV positive test result by the rapid test. Of these, 20 were confirmed by WB, one was WB negative but p24 positive and one was negative on p24 and WB. Two MSM who tested negative with the rapid test, were positive for p24 only (>= 5,0 pg/ml). Therefore, 3/23 HIV infections (13%) might have been missed, one due to a WB negative result, another two because of a negative rapid test result.
Conclusions: This study shows that our routine HIV testing procedure (rapid testing with WB confirmation without p24 testing) might miss a substantial proportion of MSM who are p24 positive, prior to the onset of antibody production, As acute infections are considered to play an important role in the ongoing transmission of HIV, one should consider to incorporate routine p24-testing in high risk populations for earlier detection of acute infections.
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