Limitations of rapid HIV-1 tests during screening for trials in Uganda: diagnostic test accuracy study

Abstract

OBJECTIVE: To evaluate the limitations of rapid tests for HIV-1. DESIGN: Diagnostic test accuracy study. SETTING: Rural Rakai, Uganda. PARTICIPANTS: 1517 males aged 15-49 screened for trials of circumcision for HIV prevention. MAIN OUTCOME MEASURES: Sensitivity, specificity, negative predictive values, and positive predictive values of an algorithm using three rapid tests for HIV, compared with the results of enzyme immunoassay and western blotting as the optimal methods. RESULTS: Rapid test results were evaluated by enzyme immunoassay and western blotting. Sensitivity was 97.7%. Among 639 samples where the strength of positive bands was coded if the sample showed positivity for HIV, the algorithm had low specificity (94.1%) and a low positive predictive value (74.0%). Exclusion of 37 samples (5.8%) with a weak positive band improved the specificity (99.6%) and positive predictive value (97.7%). CONCLUSION: Weak positive bands on rapid tests for HIV should be confirmed by enzyme immunoassay and western blotting before disclosing the diagnosis. Programmes using rapid tests routinely should use standard serological assays for quality control. Trial registration Clinical Trials NCT00425984.