The accuracy of HIV rapid testing in integrated bio-behavioral surveys of men who have sex with men across 5 Provinces in South Africa

Abstract

We describe the accuracy of serial rapid HIV testing among men who have sex with men (MSM) in South Africa and discuss the implications for HIV testing and prevention.This was a cross-sectional survey conducted at five stand-alone facilities from five provinces.Demographic, behavioral, and clinical data were collected. Dried blood spots were obtained for HIV-related testing. Participants were offered rapid HIV testing using 2 rapid diagnostic tests (RDTs) in series. In the laboratory, reference HIV testing was conducted using a third-generation enzyme immunoassay (EIA) and a fourth-generation EIA as confirmatory. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value, false-positive, and false-negative rates were determined.Between August 2015 and July 2016, 2503 participants were enrolled. Of these, 2343 were tested by RDT on site with a further 2137 (91.2%) having definitive results on both RDT and EIA. Sensitivity, specificity, positive predictive value, negative predictive value, false-positive rates, and false-negative rates were 92.6% [95% confidence interval (95% CI) 89.6–94.8], 99.4% (95% CI 98.9–99.7), 97.4% (95% CI 95.2–98.6), 98.3% (95% CI 97.6–98.8), 0.6% (95% CI 0.3–1.1), and 7.4% (95% CI 5.2–10.4), respectively. False negatives were similar to true positives with respect to virological profiles.Overall accuracy of the RDT algorithm was high, but sensitivity was lower than expected. Post-HIV test counseling should include discussions of possible false-negative results and the need for retesting among HIV negatives.

HIV Testing After a First Positive Rapid Diagnostic Test: A Role for Nucleic Acid Testing?

“…The base case and field scenario results differ due to differences in reported sensitivity/specificity, which are the most influential determinants of model results. Notably, the field-based modeled results for the WHO algorithm closely match published proportions of false-positive (5%) and false-negative (2%) results ( Table 1 ) [ 4–8 ]. When applied at scale, decimal differences in sensitivity/specificity have substantial implications: in the high-prevalence base case, for every 10 000 people tested, a 1% decrement in sensitivity causes 14 additional false-negative results, and a 1% decrement in specificity causes 3 additional false-positive results.…”

“…Algorithm accuracy is also concerning: program audits report many false-positive (range, 0%–10%) [ 4–8 ] and false-negative results (7%) [ 4 , 9 ]. Incorrect results have a substantial impact on individuals and lead to errors in estimation of program requirements and costs.…”

Age bias in survey sampling and implications for estimating HIV prevalence in men who have sex with men: insights from mathematical modelling

“…Estimates of HIV prevalence in 'key populations' (sub-populations considered to be at high risk for HIV) are very uncertain, especially in the case of men who have sex with men (MSM) and sex workers, who are in many settings 'hidden' due to criminalization or social and religious strictures. Estimates of HIV prevalence in South African MSM have been highly inconsistent, ranging from 14% to 50% [1][2][3][4][5][6][7]. Most of these prevalence studies have relied on respondent-driven sampling (RDS) to draw representative samples of MSM in specific locations and the generalizability of individual studies has been unclear.…”

“…A particular concern in the context of MSM is that RDS surveys may be biased towards younger MSM. In South African RDS studies of MSM, the median proportion of MSM who are aged <25 is 70% [1][2][3][4][5][6]14]; this compares with a proportion of only 23% in the general population of South African men in 2011 [15]. If young MSM are indeed over-represented in surveys of MSM, this may lead to HIV prevalence in MSM being under-estimated, since HIV prevalence in older MSM tends to be substantially higher than that in younger MSM [1][2][3][4].…”

Scientific Justification for the Implementation of the Integrated Model of Rapid Testing for Hiv-Infection Among Key Populations of Kazakhstan

“…Published materials of WHO UNAIDS state the need in implementation of the methodology on rapid testing for HIV-infection in Kazakhstan among key populations, nongovernmental organizations, and local communities. In the opinion of the world's leading scientists [13,14] it is recognised that rapid testing effectively provides timely access to the necessary information about HIV, routes and prevention measures, as well as treatment and social support, since the knowledge by the key populations of their HIV status is the main component of successful prevention of this infection [15,16]. The authors note that modern rapid blood and saliva tests have high sensitivity and specificity, do not require laboratory equipment, can be performed without need in clinical conditions, and fully meet the modern WHO requirements.…”