Uncertainties, work conditions and testing biases: Potential pathways to misdiagnosis in point-of-care rapid HIV testing in Zimbabwe

Abstract

Disconcerting levels of misdiagnosis are common in point-of-care rapid HIV testing programmes in sub-Saharan Africa. To investigate potential pathways to misdiagnosis, we interviewed 28 HIV testers in Zimbabwe and conducted weeklong observations at four testing facilities. Approaching adherence to national HIV testing algorithms as a social and scripted practice, dependent on the integration of certain competences, materials and meanings, our thematic analysis revealed three underlying causes of misdiagnosis: One, a lack of confidence in using certain test-kits, coupled with changes in testing algorithms and inadequate training, fed uncertainties with some testing practices. Two, difficult work conditions, including high workloads and resource-depleted facilities, compounded these uncertainties, and meant testers got distracted or resorted to testing shortcuts. Three, power struggles between HIV testers, and specific client-tester encounters created social interactions that challenged the testing process. We conclude that these contexts contribute to deviances from official and recommended testing procedures, as well as testing and interpretation biases, which may explain cases of misdiagnoses. We caution against user-error explanations to misdiagnosis in the absence of a broader recognition of how broader structural determinants affect HIV testing practices.

Rituals of care: Strategies adopted by HIV testers to avoid misdiagnosis in rapid HIV testing in Zimbabwe

“…Testers also sometimes tinkered with the testing algorithm, e.g. by administering tests in the wrong order, rather than sending clients home without being tested (Skovdal et al, 2020). In a test-and-treat environment, testers worried intensively about this, because they knew that once a client had been initiated on ART, it was almost impossible to take them off the treatment again.…”

“…who tested HIV positive with a screening test, while the second, confirmatory test showed a negative result) home and told them to come back after a week for another test, other facilities used a tie-breaker test, such as Insti, in such a scenario. As we discuss in more detail elsewhere (Skovdal et al, 2020), testers also tended to have clear preferences for particular test kits, and some testers said that they were so uncomfortable using some of the prescribed test kits in the national testing algorithm that they did not administer them. Instead, they performed confirmatory tests with the same type of test that was used for the initial diagnosis, or merely initiated ARV treatment without running a confirmatory test.…”

“…This essential conundrum formed the focus of our research, which explored how clinic staff experience and engage with rapid HIV tests, focusing on how specific clinic settings and conditions give rise to different experiences and a divergence away from the national testing algorithm and standard operating procedures (SOPs) that specify how to use rapid HIV test kits. This study was part of a larger mixed-methods study (the 'misclassification study') implemented by the Manicaland Centre for Public Health Research that investigated the scale, sources and consequences of misclassification errors in rapid HIV testing in Zimbabwe (see Skovdal et al, 2020 for further details). Approvals for the study were granted by the ethical review boards of the Medical Research Council of Zimbabwe (MRCZ/A/1865) and Imperial College London (15IC2797).…”

“…However, if the first and second tests are in disagreement, the tests must be repeated in parallel. Only if the test results should remain discordant, will a third 'tie-breaker' test be done (see Skovdal et al, 2020 for further details).…”

Comprehensive investigation of sources of misclassification errors in routine HIV testing in Zimbabwe

“…with shorter readout periods) [30], and widening eligibility criteria for repeat testing could reduce the impact of false-HIV-negative results. EQA systems could be strengthened by performing root-cause analysis [31] for false-HIV-negative cases found in proficiency testing, feeding back results to HIV testers (to increase their awareness of misdiagnoses [30]), and taking corrective action. Smartphone camera applications could be used in EQA to monitor RDT output and accuracy of testers' interpretations of these outputs in samples of testing sites.…”