INTRODUCTION: We describe the overall accuracy and performance of a serial rapid 
HIV testing algorithm used in community-based HIV testing in the context of a 
population-based household survey conducted in two sub-districts of 
uMgungundlovu district, KwaZulu-Natal, South Africa, against reference 
fourth-generation HIV-1/2 antibody and p24 antigen combination immunoassays. We 
discuss implications of the findings on rapid HIV testing programmes.
METHODS: Cross-sectional design: Following enrolment into the survey, 
questionnaires were administered to eligible and consenting participants in 
order to obtain demographic and HIV-related data. Peripheral blood samples were 
collected for HIV-related testing. Participants were offered community-based HIV 
testing in the home by trained field workers using a serial algorithm with two 
rapid diagnostic tests (RDTs) in series. In the laboratory, reference HIV 
testing was conducted using two fourth-generation immunoassays with all 
positives in the confirmatory test considered true positives. Accuracy, 
sensitivity, specificity, positive predictive value, negative predictive value 
and false-positive and false-negative rates were determined.
RESULTS: Of 10,236 individuals enrolled in the survey, 3740 were tested in the 
home (median age 24 years (interquartile range 19-31 years), 42.1% males and HIV 
positivity on RDT algorithm 8.0%). From those tested, 3729 (99.7%) had a 
definitive RDT result as well as a laboratory immunoassay result. The overall 
accuracy of the RDT when compared to the fourth-generation immunoassays was 
98.8% (95% confidence interval (CI) 98.5-99.2). The sensitivity, specificity, 
positive predictive value and negative predictive value were 91.1% (95% CI 
87.5-93.7), 99.9% (95% CI 99.8-100), 99.3% (95% CI 97.4-99.8) and 99.1% (95% CI 
98.8-99.4) respectively. The false-positive and false-negative rates were 0.06% 
(95% CI 0.01-0.24) and 8.9% (95% CI 6.3-12.53). Compared to true positives, 
false negatives were more likely to be recently infected on limited antigen 
avidity assay and to report antiretroviral therapy (ART) use.
CONCLUSIONS: The overall accuracy of the RDT algorithm was high. However, there 
were few false positives, and the sensitivity was lower than expected with high 
false negatives, despite implementation of quality assurance measures. False 
negatives were associated with recent (early) infection and ART exposure. The 
RDT algorithm was able to correctly identify the majority of HIV infections in 
community-based HIV testing. Messaging on the potential for false positives and 
false negatives should be included in these programmes.