HIV DNA AND ANTIBODIES IN SYRINGES FROM INJECTING DRUG-USERS - A COMPARISON OF DETECTION TECHNIQUES

Objective: Direct HIV testing of individual injecting drug users is no t always feasible. As an alternative, we have evaluated the sensitivit y and specificity of several techniques for detecting HIV-1-specific p roducts in used syringes. Design: Polymerase chain reaction (PCR) and antibody-capture assays were compared using syringes prepared with blo od from HIV-1-positive and -negative individuals. Methods: PCR sensiti vity was maximized, enabling detection of single copies of HIV-1-speci fic proviral DNA. The limits of detection from used syringes were dete rmined for PCR by diluting extracts and correlated to CD4+ cell counts . Similarly, limits of detection were determined for enzyme immunoassa ys (EIA) and Western blot. Results: All techniques were highly specifi c, although with PCR false-positives were detected occasionally. EIA p roved more sensitive than Western blot in detecting needles containing HIV-1-infected individuals' blood. Even after prolonged storage of sy ringes at room temperature, EIA was equal to or better than PCR as an HIV-1 detection technique. The most sensitive method for detecting HIV -1 was the viral-based EIA when the recommended predilution step was o mitted. Conclusions: EIA proved preferable to PCR because of their hig her sensitivity, absence of false-positives and easier sample preparat ion and analysis.