Detection of HIV-1 by polymerase chain reaction and culture in seronegative intravenous drug users in an inner-city emergency department

Study background: After a health care worker's unprotected exposure to a patient's blood, the current recommendation is to obtain consent from the source for serologic testing for HIV. If the test is negative, no further follow-up of the exposed provider is usually indicated. Objective: To determine if patients testing negative for HIV-1 antibody on routine serology harbor occult HIV-1 infection. Design: Cross-sectional, identity-unlinked, patient-related data and blood sample procurement for HIV-1 infection. Setting: Inner-city university hospital emergency department with high HIV-1 seroprevalence among patients. Type of participants: IV drug users not known to have HIV-1 infection. Measurements: Serum samples were analyzed for HIV-1 antibodies by enzyme immunoassay and Western blot. Peripheral mononuclear cells were analyzed for HIV-1 provirus by polymerase chain reaction and viral culture. Main results: Of 131 patients, 36 (27.5%) were Western blot-confirmed seropositive for HIV-1. Of the 95 seronegative patients, six (6.3%) were polymerase chain reaction positive, and one of these was confirmed with culture. The negative predictive value of standard serology was 93.5% with polymerase chain reaction alone and 98.9% with concordant polymerase chain reaction and culture results. Conclusion: There may be a significant number of ED patients in HIV-1 prevalent populations who have occult HIV-1 infection not detectable by serology at the time of a health care provider exposure. Although these data suggest that further prospective study is warranted to better quantify the frequency of this phenomenon, these preliminary data suggest that current Centers for Disease Control recommendations regarding provider exposures may need to be reappraised for certain situations.