Discordant rapid HIV tests: lessons from a low‐resource community

Abstract

Objectives HIV rapid antibody tests are widely used in Africa, but dual testing sometimes produces discordant results. It is not clear if discordant rapid HIV tests should always heighten suspicion by frontline health workers that early HIV infection is present. Some studies have reported that discordant rapid tests have value for identifying early HIV infection in high HIV prevalence populations. It is not known if rapid test performance influenced this conclusion, or if this observation will hold true for low HIV prevalence populations. We therefore explored the occurrence of discordant rapid HIV tests in a low-resource community. Methods A cross-sectional sample of HIV status-unaware adults with recent exposure to unsafe sex was assessed using a validated risk-based tool (University of North Carolina (UNC)-Malawi Risk Screening Score) for acute HIV infection. Participants received rapid testing with Determine™ HIV 1/2 and Uni-Gold™ HIV assays, plus plasma HIV-1 antigen testing with the COBAS® Ampliprep/COBAS® Taqman® HIV-1 assay, followed by western blot in those with detected HIV-1 antigen. Results Of 408 participants, 1.0% were confirmed to have established HIV infection. The discordance between rapid tests at initial screening was 2.45 and 2.94% when the two assays were used sequentially and simultaneously, respectively. Discordant rapid tests were strongly associated with risk scores > 2 [odds ratio (OR) 10.88; 95% confidence interval (CI) 2.35–50.43], and with detected HIV-1 RNA (OR 26.06; 95% CI 3.91–173.60). Conclusions When the sample occurrence of discordance between the first and second tests is below 5%, discordant rapid tests in an adult with sexual risk behaviour should trigger strong suspicion of early HIV infection in low HIV prevalence populations.

Early HIV infection is associated with reduced proportions of gamma delta T subsets as well as high creatinine and urea levels

“…It is possible that systemic immune activation peaked after a reasonable compartment of γδ and DNT cells have been depleted which may occur during seeding of HIV virions into renal reservoirs as previously described . In most sub‐Saharan African countries, treatment initiation for HIV‐infected individuals' starts in the chronic stage of infection despite the recently introduced ‘test and treat’ policy, reason being that most HIV‐infected individuals are detected at this period . Early HIV immunotherapy may be useful in preventing the depletion of γδ and DNT T cells proportions very early in infection before systemic immune activation.…”

The diagnostic accuracy of the HIV 1/2/subtype O Tri‐line rapid test compared with ELISA: A pilot study

“…The cause for the five false‐negative results could not be determined; however, acute HIV infection (Adetunji et al., 2018), improper administration of HIV‐TRT and severe immunosuppression cannot be ruled out. In line with findings in other studies, females and patients aged 20–41 are most likely to (Mbachu et al., 2015; UNAIDS, 2018) present with HIV infection in our setting.…”

“…The sensitivity and specificity of RTs have been shown to be variable in several studies (Adetunji et al., 2018; Gray et al., 2007; Patel et al., 2012; Piwowar‐Manning et al., 2010; Wolpaw et al., 2010). Given this variation in performance, the sensitivity and specificity of RTs remain a justifiable concern.…”

Analysis of antibodies involved in cases of discordant and indeterminate HIV serology in Togo from 2016 to 2018

“…[4][5][6] Thus, the wide distribution of RDTs in these countries and their use out of accredited medical laboratories raises questions about their reliability in terms of sensitivity and specificity. [7][8][9][10] Consequently, the use of these tests is often based on algorithms combining several tests. 11,12 In Togo, the algorithm for the biological diagnosis of HIV infection in adults and children over 18 months requires for the performing of a screening test called "test 1" which must be confirmed by a "test 2" if the first test is reactive.…”