To err is human, to correct is public health: a systematic review examining poor quality testing and misdiagnosis of HIV status

Quantitative reagent monitoring in paper-based electrochemical rapid diagnostic tests

Paper-based rapid diagnostic tests (RDTs) are an essential component of modern healthcare, particularly for the management of infectious diseases. Despite their utility, these capillary-driven RDTs are compromised by high failure rates, primarily caused by user error. This limits their utility in complex assays that require multiple user operations. Here, we demonstrate how this issue can be directly addressed through continuous electrochemical monitoring of reagent flow inside an RDT using embedded graphenized electrodes. Our method relies on applying short voltage pulses and measuring variations in capacitive discharge currents to precisely determine the flow times of injected samples and reagents. This information is reported to the user, guiding them through the testing process, highlighting failure cases and ultimately decreasing errors. Significantly, the same electrodes can be used to quantify electrochemical signals from immunoassays, providing an integrated solution for both monitoring assays and reporting results. We demonstrate the applicability of this approach in a serology test for the detection of anti-SARS-CoV-2 IgG in clinical serum samples. This method paves the way towards "smart" RDTs able to continuously monitor the testing process and improve the robustness of point-of-care diagnostics.

Outcomes of discordant HIV screening test results at a southern academic medical center

OBJECTIVE

The aim of this study was to examine outcomes of follow-up for persons with discordant fourth-generation HIV screening test results.

DESIGN

A retrospective chart review.

METHODS

We analyzed the electronic health record at the Medical University of South Carolina for a 10-year period spanning 2012-2022 to identify instances of discordant HIV screening test results, wherein initial antigen/antibody screening was positive, but reflex confirmatory testing for HIV-1 and HIV-2 antibodies was negative. We reviewed individual records to evaluate clinical follow-up and determine if the discordant test represented an acute HIV infection, a false-positive result, or was unresolved.

RESULTS

We identified 199 testing instances with discordant results. Most discordant results ( n  = 115) were subsequently determined to reflect a false-positive test, while 56 were unresolved without documented follow-up testing. Twenty-eight cases of acute HIV infection were identified of which 26 were linked to care within a month of initial testing. Two acute HIV cases were not identified in real time leading to delay in diagnosis and care. Testing done in the context of infectious symptoms and testing performed in the emergency department were associated with increased odds of a discordant test ultimately reflecting acute HIV infection.

CONCLUSION

These results demonstrate the importance of appropriate and timely follow-up for discordant HIV screening test results.

Brief Report: Self-Reported HIV-Positive Status but Subsequent HIV-Negative Test Results in Population-Based HIV Impact Assessment Survey Participants-11 Sub-Saharan African Countries, 2015-2018

BACKGROUND

HIV testing is a critical step to accessing antiretroviral therapy (ART) because early diagnosis can facilitate earlier initiation of ART. This study presents aggregated data of individuals who self-reported being HIV-positive but subsequently tested HIV-negative during nationally representative Population-Based HIV Impact Assessment surveys conducted in 11 countries from 2015 to 2018.

METHOD

Survey participants aged 15 years or older were interviewed by trained personnel using a standard questionnaire to determine HIV testing history and self-reported HIV status. Home-based HIV testing and counseling using rapid diagnostic tests with return of results were performed by survey staff according to the respective national HIV testing services algorithms on venous blood samples. Laboratory-based confirmatory HIV testing for all participants identified as HIV-positives and self-reported positives, irrespective of HIV testing results, was conducted and included Geenius HIV-1/2 and DNA polymerase chain reaction if Geenius was negative or indeterminate.

RESULTS

Of the 16,630 participants who self-reported as HIV-positive, 16,432 (98.6%) were confirmed as HIV-positive and 198 (1.4%) were HIV-negative by subsequent laboratory-based testing. Participants who self-reported as HIV-positive but tested HIV-negative were significantly younger than 30 years, less likely to have received ART, and less likely to have received a CD4 test compared with participants who self-reported as HIV-positive with laboratory-confirmed infection.

CONCLUSIONS

A small proportion of self-reported HIV-positive individuals could not be confirmed as positive, which could be due to initial misdiagnosis, deliberate wrong self-report, or misunderstanding of the questionnaire. As universal ART access is expanding, it is increasingly important to ensure quality of HIV testing and confirmation of HIV diagnosis before ART initiation.

Evaluating the sensitivity and specificity of Determine™ HIV-1/2 rapid test using a 0.01M phosphate-buffered saline produced at the Medical Research Council Unit The Gambia for the diagnosis of HIV

BACKGROUND

Human immunodeficiency virus (HIV) rapid diagnostic tests (RDTs) are widely used. However, buffer stockouts commonly lead to utilising non-approved liquids, resulting in errors. Our aim was to evaluate the diagnostic accuracy of an alternative buffer.

METHODS

Paired Determine HIV-1/2 rapid tests with commercial buffer and locally produced 0.01M phosphate-buffered saline (PBS) were performed on consecutive consenting individuals requiring HIV testing. Serum samples were sent for confirmation through the local gold-standard algorithm (Murex HIV Ag/Ab, Hexagon HIV with/without Geenius HIV 1/2). Test accuracy, κ and exact McNemar's test were also carried out.

RESULTS

Of 167 participants, 137 had confirmatory testing. The sensitivity of the Determine HIV-1/2 test using PBS compared with the gold standard was 100% (95% confidence interval [CI] 90.5 to 100) with a specificity of 98% (95% CI 92.9 to 99.8). The κ value was 0.94 compared with the gold standard and 0.92 compared with the Determine HIV-1/2 test using the commercial buffer. McNemar's test showed no evidence of differing sensitivities. Due to operational constraints, the study included 37 of the 49 positive cases as determined by the sample size calculation, resulting in an attained power of 80% instead of the intended 90%.

CONCLUSIONS

These results suggest that 0.01M PBS is an alternative solution for Determine HIV-1/2 when buffer stockouts occur.

Country adoption of WHO 2019 guidance on HIV testing strategies and algorithms: a policy review across the WHO African region

OBJECTIVES

In 2019, the WHO released guidelines on HIV testing service (HTS). We aim to assess the adoption of six of these recommendations on HIV testing strategies among African countries.

DESIGN

Policy review.

SETTING

47 countries within the WHO African region.

PARTICIPANTS

National HTS policies from the WHO African region as of December 2021.

PRIMARY AND SECONDARY OUTCOME MEASURES

Uptake of WHO recommendations across national HTS policies including the standard three-test strategy; discontinuation of a tiebreaker test to rule in HIV infection; discontinuation of western blotting (WB) for HIV diagnosis; retesting prior to antiretroviral treatment (ART) initiation and the use of dual HIV/syphilis rapid diagnostic tests (RDTs) in antenatal care. Country policy adoption was assessed on a continuum, based on varying levels of complete adoption.

RESULTS

National policies were reviewed for 96% (n=45/47) of countries in the WHO African region, 38% (n=18) were published before 2019 and 60% (n=28) adopted WHO guidance. Among countries that had not fully adopted WHO guidance, not yet adopting a three-test strategy was the most common reason for misalignment (45%, 21/47); of which 31% and 22% were in low-prevalence (<5%) and high-prevalence (≥5%) countries, respectively. Ten policies (21%) recommended the use of WB and 49% (n=23) recommended retesting before ART initiation. Dual HIV/syphilis RDTs were recommended in 45% (n=21/47) of policies.

CONCLUSIONS

Many countries in the African region have adopted WHO-recommended HIV testing strategies; however, efforts are still needed to fully adopt WHO guidance. Countries should accelerate their efforts to adopt and implement a three-test strategy, retesting prior to ART initiation and the use of dual HIV/syphilis RDTs.

Ensuring diagnostic testing accuracy for patient care and public health- COVID-19 testing scale-up from an EQA provider's perspective

In response to the coronavirus pandemic (COVID-19) and scale up of diagnostic testing, the Canadian Microbiology Proficiency Testing program created a new proficiency testing (PT) program for the molecular and antigen detection of SARS-CoV-2. The program was geared to point of care testing (POCT) sites located in each of the eight provincial Health Authorities across British Columbia, Canada, with the intention to monitor testing quality. The PT program consisted of 6 shipments in a year, each containing a set of 4 samples either positive for SARS-CoV-2 virus or negative. The program began with initial 23 sites enrolling in March 2021, expanding to >100 participants by December 2021. After the first two surveys, it was observed that testing performance (accuracy) was consistently acceptable for sites using nucleic acid technology (NAT), however performance by sites using rapid antigen detection (RAD) methods was poor, especially when testing the weakly positive samples. A root cause investigation of poor testing performance revealed gaps in the execution of testing methods and also in results interpretation. These quality issues were most commonly associated with new testers who lacked experience with diagnostic testing. Tester training and mentoring was reinforced as was retraining of personnel; sample processing instructions were modified, and a training video was also created for testing sites. As a result of these interventions, sites improved their testing accuracy and the performance of POCT sites using RAD methods came to more closely match the performance of sites utilizing NAT. Overall, the PT program was highly successfully and improved quality of testing in the province. This work demonstrates the critical value of an external quality assessment (EQA) partner towards improving patient and public health and safety, especially when testing is conducted outside of an accredited medical laboratory setting.

Repeated false-negative HIV rapid test results in a patient presenting to care with advanced HIV disease: A case report

Severe immunosuppression has been reported as one of the causes of a false-negative HIV rapid test result. Guidelines on what tests should be performed in adult patients presenting with severe immunosuppression despite a negative HIV rapid test result are lacking. This is the second case report of a false-negative HIV rapid test results in a patient presenting with advanced HIV disease in Tanzania.

Seroconversion, seroreversion, and serowaffling among participants initiating antiretroviral therapy in Project DETECT

BACKGROUND

Incomplete HIV seroconversion and seroreversion are increasingly documented by testing and pre-exposure prophylaxis programs more than previously recognized. This analysis reports on incomplete seroconversion and seroreversion by specimen and test type among Project DETECT participants.

METHODS

Project DETECT included a longitudinal study of point-of-care tests. Participants were categorized as having "incomplete seroconversion" if all timepoints had ≥1 nonreactive test at study censoring. Among participants with incomplete seroconversion, we defined "seroreversion" as sustained regression to nonreactive for any test following a reactive result. We define "serowaffling" as any reactive result followed by a nonreactive and then reactive result. We used Fisher's exact tests to explore relationships between Fiebig stage at ART initiation and incomplete seroconversion, seroreversion, and serowaffling.

RESULTS

Twenty of 1940 Project DETECT participants met criteria for this subset. Ten participants had complete seroconversion after a median of 23 (IQR 16-47) days following initial positive tests. Ten participants had incomplete seroconversion, eight of whom had seroreversion. Incomplete seroconversion with persistent nonreactive tests was seen only with oral fluid (OF). Of eight participants with seroreversion, all experienced seroreversion of OF tests if the test was ever reactive (n = 6); seroreversion occurred in fingerstick and venipuncture tests in two participants. Serowaffling occurred in nine (45%) participants. No associations were seen between Fiebig stage at ART start and complete seroconversion, seroregression, or serowaffling in our sample.

CONCLUSIONS

OF tests may be particularly susceptible to providing false-negative results. Seroreversion and incomplete seroconversion among individuals on antiretroviral treatment may represent a growing problem for HIV testing and treatment programs.

Temporal discrepancies in "rapid" HIV testing: explaining misdiagnoses at the point-of-care in Zimbabwe

BACKGROUND

Rapid diagnostic tests have revolutionized the HIV response in low resource and high HIV prevalence settings. However, disconcerting levels of misdiagnosis at the point-of-care call for research into their root causes. As rapid HIV tests are technologies that cross borders and have inscribed within them assumptions about the context of implementation, we set out to explore the (mis)match between intended and actual HIV testing practices in Zimbabwe.

METHODS

We examined actual HIV testing practices through participant observations in four health facilities and interviews with 28 rapid HIV testers. As time was identified as a key sphere of influence in thematic analyses of the qualitative data, a further layer of analysis juxtaposed intended (as scripted in operating procedures) and actual HIV testing practices from a temporal perspective.

RESULTS

We uncover substantial discrepancies between the temporal flows assumed and inscribed into rapid HIV test kits (their intended use) and those presented by the high frequency testing and low resource and staffing realities of healthcare settings in Zimbabwe. Aside from pointing to temporal root causes of misdiagnosis, such as the premature reading of test results, our findings indicate that the rapidity of rapid diagnostic technologies is contingent on a slow, steady, and controlled environment. This not only adds a different dimension to the meaning of "rapid" HIV testing, but suggests that errors are embedded in the design of the diagnostic tests and testing strategies from the outset, by inscribing unrealistic assumptions about the context within which they used.

CONCLUSION

Temporal analyses can usefully uncover difficulties in attuning rapid diagnostic test technologies to local contexts. Such insight can help explain potential misdiagnosis 'crisis points' in point-of-care testing, and the need for public health initiatives to identify and challenge the underlying temporal root causes of misdiagnosis.

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

A growing number of studies highlight high levels of misdiagnosis in the scale-up of HIV rapid testing programmes, which often remain invisible to individual testers. Drawing on interviews with HIV testers and observations in four health facilities in Zimbabwe, we show that testers navigated the translation of the standardised, dis-embodied norms of laboratory-based testing into the body work of point-of-care testing through ritualisation of laboratory-practices in their daily clinical work. Yet, this was interrupted through the challenging work conditions the testers face. They ritualised careful procedures, forcing themselves to focus even if queues were long, and making quality assurance procedures part of their daily routine. They actively tried to reduce their workloads and double-checked and discussed unexpected results, especially when a test result did not match their evaluation of clients' circumstances or clinical status. This helped not only to increase confidence in the authenticity of their diagnosis, but also to share responsibility for potential errors. Existing approaches to tackle the problem of misdiagnosis through quality assurance (QA) procedures mainly focus on adjusting individual testers' performance and ensuring that basic testing resources were present, thus falling short of creating a work environment that is conducive to high quality testing.

Using trajectory modeling of spatio-temporal trends to illustrate disparities in COVID-19 death in flint and Genesee County, Michigan

COVID-19's rapid onset left many public health entities scrambling. But establishing community-academic partnerships to digest data and create advocacy steps offers an opportunity to link research to action. Here we document disparities in COVID-19 death uncovered during a collaboration between a health department and university research center. We geocoded COVID-19 deaths in Genesee County, Michigan, to model clusters during two waves in spring and fall 2020. We then aggregated these deaths to census block groups, where group-based trajectory modeling identified latent patterns of change and continuity. Linking with socioeconomic data, we identified the most affected communities. We discovered a geographic and racial gap in COVID-19 deaths during the first wave, largely eliminated during the second. Our partnership generated added and immediate value for community partners, including around prevention, testing, treatment, and vaccination. Our identification of the aforementioned racial disparity helped our community nearly eliminate disparities during the second wave.

Improving the quality of HIV rapid testing in Ghana using the dried tube specimen-based proficiency testing program

BACKGROUND

The introduction of human immunodeficiency virus (HIV) antibody rapid testing (RT) in resource-limited settings has proven to be a successful intervention to increase access to prevention measures and improve timely linkage to care. However, the quality of testing has not always kept pace with the scale-up of this testing strategy. To monitor the accuracy of HIV RT test results, a national proficiency testing (PT) program was rolled out at selected testing sites in Ghana using the dried tube specimen (DTS) approach.

METHODS

Between 2015 and 2018, 635 HIV testing sites, located in five regions and supported by the U.S. President's Emergency Plan for AIDS Relief (PEPFAR), were enrolled in the HIV PT program of the Ghana Health Service National AIDS/STI Control Programme. These sites offered various services: HIV Testing and Counselling (HTC), prevention of mother-to-child transmission (PMTCT) and Antiretroviral Treatment (ART). The PT panels, composed of six DTS, were prepared by two regional laboratories, using fully characterized plasma obtained from the regional blood banks and distributed to the testing sites. The results were scored by the PT providers according to the predefined acceptable performance criteria which was set at ≥ 95%.

RESULTS

Seven rounds of PT panels were completed successfully over three years. The number of sites enrolled increased from 205 in round 1 (June 2015) to 635 in round 7 (December 2018), with a noticeable increase in Greater Accra and Eastern regions. The average participation rates of enrolled sites ranged from 88.0% to 98.0% across the PT rounds. By round 7, HTC (257/635 (40.5%)) and PMTCT (237/635 (37.3%)) had a larger number of sites that participated in the PT program than laboratory (106/635 (16.7%)) and ART (12/635 (1.9%)) sites. The average testing performance rate improved significantly from 27% in round 1 to 80% in round 7 (p < 0.001). The highest performance rate was observed for ART (100%), HTC (92%), ANC/PMTCT (90%) and Laboratory (89%) in round 5.

CONCLUSION

The DTS PT program showed a significant increase in the participation and performance rates during this period. Sub-optimal performances observed was attributed to non-compliance to the national testing algorithm and testing technique. However, the implementation of review meetings, peer-initiated corrective action, supportive supervisory training, and mentorship proved impactful. The decentralized approach to preparing the PT panels ensured ownership by the region and districts.

Implementation of Novel Quality Assurance Program for Hepatitis C Viral Load Point of Care Testing

All patients should have access to accurate and timely test results. The introduction of point of care testing (PoCT) for infectious diseases has facilitated access to those unable to access traditional laboratory-based medical testing, including those living in remote and regional locations, or individuals who are marginalized or incarcerated individuals. In many countries, laboratory testing for infectious diseases, such as hepatitis C virus (HCV), is performed in a highly regulated environment. However, this is not the case for PoCT, where testing is performed by non-laboratory staff and quality controls are often lacking. An assessment of the provision of laboratory-based quality assurance to PoCT for infectious disease was conducted and the barriers to participation identified. A novel approach to providing quality assurance to PoCT sites, in particular those testing for HCV, was designed and piloted. This novel approach incudes identifying and validating sample types that are inactivated and stable at ambient temperature, creating cost-effective supply chains to facilitate logistics of samples, and the development of a smart phone-enabled portal for data entry and analyses. The creation and validation of this approach to quality assurance of PoCT removes the barriers to participation and acts to improve the quality and accuracy of testing, reduce errors and waste, and improve patient outcomes.

The (in)visibility of misdiagnosis in point-of-care HIV testing in Zimbabwe

There is a global trend to introduce point-of-care diagnostic tests, enabling healthcare workers at any level to test, provide results, and initiate immediate treatment if necessary. This article explores how healthcare workers conducting rapid HIV tests - in contexts of limited external quality assurance mechanisms - ascertain the accuracy of their test results. Drawing on interview data and participant observations from health facilities in Zimbabwe, we open the black box of misdiagnosis (in)visibility and reveal a range of proxies and markers that HIV testers draw on to develop certainty, or question, the reliability of their diagnostic classifications.

Evaluation of the Nigeria national HIV rapid testing algorithm

Human Immunodeficiency Virus (HIV) diagnosis remains the gateway to HIV care and treatment. However, due to changes in HIV prevalence and testing coverage across different geopolitical zones, it is crucial to evaluate the national HIV testing algorithm as false positivity due to low prevalence could be detrimental to both the client and the service delivery. Therefore, we evaluated the performance of the national HIV rapid testing algorithm using specimens collected from multiple HIV testing services (HTS) sites and compared the results from different HIV prevalence levels across the six geopolitical zones of Nigeria. The evaluation employed a dual approach, retrospective, and prospective. The retrospective evaluation focused on a desktop review of program data (n = 492,880) collated from patients attending routine HTS from six geopolitical zones of Nigeria between January 2017 and December 2019. The prospective component utilized samples (n = 2,895) collected from the field at the HTS and tested using the current national serial HIV rapid testing algorithm. These samples were transported to the National Reference Laboratory (NRL), Abuja, and were re-tested using the national HIV rapid testing algorithm and HIV-1/2 supplementary assays (Geenius to confirm positives and resolve discordance and multiplex assay). The retrospective component of the study revealed that the overall proportion of HIV positives, based on the selected areas, was 5.7% (28,319/492,880) within the study period, and the discordant rate between tests 1 and 2 was 1.1%. The prospective component of the study indicated no significant differences between the test performed at the field using the national HIV rapid testing algorithm and the re-testing performed at the NRL. The comparison between the test performed at the field using the national HIV rapid testing algorithm and Geenius HIV-1/2 supplementary assay showed an agreement rate of 95.2%, while that of the NRL was 99.3%. In addition, the comparison of the field results with HIV multiplex assay indicated a sensitivity of 96.6%, the specificity of 98.2%, PPV of 97.0%, and Kappa Statistic of 0.95, and that of the NRL with HIV multiplex assay was 99.2%, 99.4%, 99.0%, and 0.99, respectively. Results show that the Nigeria national serial HIV rapid testing algorithm performed very well across the target settings. However, the algorithm's performance in the field was lower than the performance outcomes under a controlled environment in the NRL. There is a need to target testers in the field for routine continuous quality improvement implementation, including refresher trainings as necessary.

Validation of mailed via postal service dried blood spot cards on commercially available HIV testing systems

The demand for HIV testing using dried blood spots (DBS) has increased recently. However, DBS is not an approved sample for HIV testing in Japan. This study examined the validation of HIV testing with DBS, prepared at the laboratory or remotely and mailed via postal service to the laboratory. DBS were punched out from a 5.5 mm diameter circle on filter paper, then eluted with 600 μL of phosphate buffered saline overnight at 4℃, and analyzed by Lumipulse S HIVAg/Ab (LUM). The mean LUM count of DBS was 237.4-times diluted compared to titrated plasma. Repeated sample testing showed that although LUM count of DBS decreased slightly with increase in sample storage time (up to one month), it did not affect the result of HIV testing with DBS. Based on testing of 50 HIV+ confirmed cases and 50 HIV- persons, the estimated sensitivity was 98% (49/50) with a specificity of 100% when the cut-off value is 0.5. The single false negative case was a patient with undetectable viral load over the last 10 years, resulting in a decrease of antibody titer below the cut-off level. In conclusion, although DBS cannot completely replace plasma in HIV testing because the sensitivity was a little lower than that of plasma, it can be potentially useful for a screening test by self-finger-prick and postal service use. This will allow people to receive HIV testing without visiting public health centers.

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Purpose

The establishment of community-academic partnerships to digest data and create actionable policy and advocacy steps is of continuing importance. In this paper, we document COVID-19 racial and geographic disparities uncovered via a collaboration between a local health department and university research center.

Methods

We leverage individual level data for all COVID-19 cases aggregated to the census block group level, where group-based trajectory modeling was employed to identify latent patterns of change and continuity in COVID-19 diagnoses.

Results

Linking with socioeconomic data from the census, we identified the types of communities most heavily affected by each of Michigan's two waves (in spring and fall of 2020). This includes a geographic and racial gap in COVID-19 cases during the first wave, which is largely eliminated during the second wave.

Conclusions

Our work has been extremely valuable for community partners, informing community-level response toward testing, treatment, and vaccination. In particular, identifying and conducting advocacy on the sizeable racial disparity in COVID-19 cases during the first wave in spring 2020 helped our community nearly eliminate disparities throughout the second wave in fall 2020.

Findings from a novel and scalable community-based HIV testing approach to reduce the time required to complete point-of-care HIV testing in South Africa

BACKGROUND

Mobile HIV testing approaches are a key to reaching the global targets of halting the HIV epidemic by 2030. Importantly, the number of clients reached through mobile HIV testing approaches, need to remain high to maintain the cost-effectiveness of these approaches. Advances in rapid in-vitro tests such as INSTI® HIV-1/HIV-2 (INSTI) which uses flow-through technologies, offer opportunities to reduce the HIV testing time to about one minute. Using data from a routine mobile HTS programme which piloted the use of the INSTI point-of-care (POC) test, we sought to estimate the effect of using a faster test on client testing volumes and the number of people identified to be living with HIV, in comparison with standard of care HIV rapid tests.

METHODS

In November 2019, one out of four mobile HTS teams operating in Ekurhuleni District (South Africa) was randomly selected to pilot the field use of INSTI-POC test as an HIV screening test (i.e., the intervention team). We compared the median number of clients tested for HIV and the number of HIV-positive clients by the intervention team with another mobile HTS team (matched on performance and area of operation) which used the standard of care (SOC) HIV screening test (i.e., SOC team).

RESULTS

From 19 to 20 December 2019, the intervention team tested 7,403 clients, and the SOC team tested 2,426 clients. The intervention team tested a median of 442 (IQR: 288-522) clients/day; SOC team tested a median of 97 (IQR: 40-187) clients/day (p<0.0001). The intervention team tested about 180 more males/day compared to the SOC team, and the median number of adolescents and young adults tested/day by the intervention team were almost four times the number tested by the SOC team. The intervention team identified a higher number of HIV-positive clients compared to the SOC team (142 vs. 88), although the proportion of HIV-positive clients was lower in the intervention team due to the higher number of clients tested.

CONCLUSIONS

This pilot programme provides evidence of high performance and high reach, for men and young people through the use of faster HIV rapid tests, by trained lay counsellors in mobile HTS units.

Deep learning of HIV field-based rapid tests

Although deep learning algorithms show increasing promise for disease diagnosis, their use with rapid diagnostic tests performed in the field has not been extensively tested. Here we use deep learning to classify images of rapid human immunodeficiency virus (HIV) tests acquired in rural South Africa. Using newly developed image capture protocols with the Samsung SM-P585 tablet, 60 fieldworkers routinely collected images of HIV lateral flow tests. From a library of 11,374 images, deep learning algorithms were trained to classify tests as positive or negative. A pilot field study of the algorithms deployed as a mobile application demonstrated high levels of sensitivity (97.8%) and specificity (100%) compared with traditional visual interpretation by humans-experienced nurses and newly trained community health worker staff-and reduced the number of false positives and false negatives. Our findings lay the foundations for a new paradigm of deep learning-enabled diagnostics in low- and middle-income countries, termed REASSURED diagnostics1, an acronym for real-time connectivity, ease of specimen collection, affordable, sensitive, specific, user-friendly, rapid, equipment-free and deliverable. Such diagnostics have the potential to provide a platform for workforce training, quality assurance, decision support and mobile connectivity to inform disease control strategies, strengthen healthcare system efficiency and improve patient outcomes and outbreak management in emerging infections.

Community-based HIV self-testing: a cluster-randomised trial of supply-side financial incentives and time-trend analysis of linkage to antiretroviral therapy in Zimbabwe

BACKGROUND

HIV self-testing (HIVST) requires linkage to post-test services to maximise its benefits. We evaluated effect of supply-side incentivisation on linkage following community-based HIVST and evaluated time-trends in facility-based antiretroviral therapy (ART) initiations.

METHODS

From August 2016 to August 2017 community-based distributors (CBDs) in 38 rural Zimbabwean communities distributed HIVST door-to-door in 19-25 day campaigns. Communities were allocated (1:1) using constrained randomisation to either one-off US$50 remuneration per CBD (non-incentive arm), or US$50 plus US$0.20 incentive per client visiting mobile-outreach services (conditional-incentive arm). The primary outcome, assessed by population survey 6 weeks later, was self-reported uptake of any clinic service, analysed with random-effects logistic regression. Separately, non-randomised difference-in-differences in monthly ART initiations were analysed for three time periods (6 months baseline; HIVST campaign; 3 months after) at public clinics with (40 clinics) and without (124 clinics) HIVST distribution in catchment area.

FINDINGS

A total of 445 conditional-incentive CBDs distributed 39 205 HIVST kits (mean/CBD: 88; 95% CI: 85 to 92) and 447 non-incentive CBDs distributed 41 173 kits (mean/CBD: 93; 95% CI: 89 to 96). Survey participation was 7146/8566 (83.4%), with 3593 (50.3%) reporting self-testing including 1305 (18.3%) previously untested individuals. Use of clinic services post-HIVST was similar in conditional-incentive (1062/3698, 28.7%) and non-incentive (1075/3448, 31.2%) arms (adjusted risk ratio (aRR) 0.94, 95% CI: 0.86 to 1.03). Confirmatory testing by newly diagnosed/untreated HIVST+clients was, however, higher (conditional-incentive: 25/33, 75.8% vs non-incentive: 20/40, 50.0%: aRR: 1.59, 95% CI: 1.05 to 2.39). In total, 12 808 ART initiations occurred, with no baseline or postcampaign differences between initiation rates in HIVST versus non-HIVST clinics, but initiation rates increased from 7.31 to 9.59 initiations per month in HIVST clinics during distribution, aRR: 1.27, 95% CI 1.17 to 1.39.

CONCLUSIONS

Community-based HIVST campaigns achieved high testing uptake, temporally associated with increased demand for ART. Small supply-side incentives did not affect general clinic usage but may have increased confirmatory testing for newly diagnosed HIVST positive participants.

TRIAL REGISTRATION NUMBER

PACTR201607001701788.

Country adherence to WHO recommendations to improve the quality of HIV diagnosis: a global policy review

Introduction

Ensuring a correct and timely HIV diagnosis is critical. WHO publishes guidelines on HIV testing strategies that maximise the likelihood of correctly determining one’s HIV status. A review of national HIV testing policies in 2014 found low adherence to WHO guidelines. We updated this review to determine adherence to current recommendations.

Methods

We conducted a comprehensive policy review through April 2018. We extracted data on HIV testing strategies, recommendations on HIV retesting prior to antiretroviral therapy (ART) initiation and pre-exposure prophylaxis (PrEP)-related HIV testing information. Descriptive analyses disaggregated by region were conducted to ascertain adherence to recommendations and to describe testing strategy characteristics.

Results

Of 91 policies included, 26% (n=24/91) adhered to WHO recommendations. Having a two-assay testing strategy to rule-in HIV infection as opposed to the recommended three-assay testing strategy was a major reason for non-adherence. Of 72 country policies providing sufficient information, 31% (n=22) recommended retesting for HIV prior to initiating ART. Of 25 countries and two regions reporting PrEP-related HIV testing guidelines, almost all recommended testing prior to initiating PrEP and every 3 months during PrEP use.

Conclusions

Global adherence to WHO recommendations for HIV testing strategies have improved since 2014 but remain low. We found adherence existed on a continuum. Such a system provides insights into how countries can move towards adherence by making relatively minor changes to testing strategies. Guidance from WHO on the role of new HIV testing technologies within testing algorithms and identifying ways to simplify testing guidance is warranted.

Reconfirming HIV serostatus in three West African Military ART clinics

BACKGROUND

HIV rapid diagnostic test (RDT) algorithms have been successfully employed worldwide to accelerate critically important HIV testing. Deviations from the algorithm and processing errors have been associated with inaccurate algorithm results. Positive RDT algorithm results should be confirmed prior to HIV clinic enrollment, but compliance varies. We sought to retest HIV status of patients in three West African military HIV clinics.

SETTING

Military HIV clinics in Lome, Togo; Freetown, Sierra Leone; and Monrovia, Liberia METHODS: Patients coming for routine HIV clinic visits were approached for enrollment. Consenting participants completed a 15-minute questionnaire and provided blood samples for both national and WHO-recommended HIV RDT algorithms, and HIV ELISA (plus HIV PCR if HIV ELISA negative).

RESULTS

In total, 817 participants provided data: 374 in Togo, 360 in Sierra Leone, and 83 in Liberia. One participant from Liberia was HIV-negative (although follow-up testing was positive). Two of 807 participants on antiretroviral treatment (ART) had inconclusive algorithms, while 2 of 10 participants not on ART had algorithms, for 4 total based on the WHO-approved algorithm. Using the national algorithms, only 3 were inconclusive. A substantial proportion of the cohort had taken ART for over 6 years (25-46%, depending on the site).

CONCLUSION

HIV RDT retesting in three military HIV clinics did not uncover significant numbers of misclassified HIV patients. There was no significant difference between national and WHO-recommended RDT algorithms, although the study was underpowered to detect a difference. Antiretroviral treatment was not associated with increased rates of inconclusive RDT algorithm results.

Evaluating Point-of-Care Nucleic Acid Tests in Adult Human Immunodeficiency Virus Diagnostic Strategies: A Côte d'Ivoire Modeling Analysis

BACKGROUND

The World Health Organization (WHO) human immunodeficiency virus (HIV) diagnostic strategy requires 6 rapid diagnostic tests (RDTs). Point-of-care nucleic acid tests (POC NATs) are costlier, less sensitive, but more specific than RDTs.

METHODS

We simulated a 1-time screening process in Côte d'Ivoire (CI; undiagnosed prevalence: 1.8%), comparing WHO- and CI-recommended RDT-based strategies (RDT-WHO, RDT-CI) and an alternative: POC NAT to resolve RDT discordancy (NAT-Resolve). Costs included assays (RDT: $1.47; POC NAT: $27.92), antiretroviral therapy ($6-$22/month), and HIV care ($27-$38/month). We modeled 2 sensitivity/specificity scenarios: high-performing (RDT: 99.9%/99.1%; POC NAT: 95.0%/100.0%) and low-performing (RDT: 91.1%/82.9%; POC NAT: 93.3%/99.5%). Outcomes included true-positive (TP), false-positive (FP), true-negative (TN), or false-negative (FN) results; life expectancy; costs; and incremental cost-effectiveness ratios (ICERs: $/year of life saved [YLS]; threshold ≤$1720/YLS [per-capita gross domestic product]).

RESULTS

Model-projected impacts of misdiagnoses were 4.4 years lost (FN vs TP; range, 3.0-13.0 years) and a $5800 lifetime cost increase (FP vs TN; range, $590-$14 680). In the high-performing scenario, misdiagnoses/10 000 000 tested were lowest for NAT-Resolve vs RDT-based strategies (FN: 409 vs 413-429; FP: 14 vs 21-28). Strategies had similar life expectancy (228 months) and lifetime costs ($220/person) among all tested; ICERs were $3450/YLS (RDT-CI vs RDT-WHO) and $120 910/YLS (NAT-Resolve vs RDT-CI). In the low-performing scenario, misdiagnoses were higher (FN: 22 845-30 357; FP: 83 724-112 702) and NAT-Resolve was cost-saving.

CONCLUSIONS

We projected substantial clinical and economic impacts of misdiagnoses. Using POC NAT to resolve RDT discordancy generated the fewest misdiagnoses and was not cost-effective in high-performing scenarios, but may be an important adjunct to existing RDT-based strategies in low-performing scenarios.

Near misdiagnosis of acute HIV-infection with ELISA-Western Blot scheme: Time for mindset change

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Many health care providers still rely upon the ELISA-Western blot scheme for HIV-diagnosis.

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Western blot may fail to detect an acute HIV-infection.

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Point of Care settings using rapid tests should consider anamnesis and patient risk assessment for an accurate HIV-Testing.

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Discordant HIV-testing results require knowledgeable counseling.

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Health care providers should be aware and updated about changes in HIV-testing guidelines.

Some HIV-infection diagnostic guidelines and health care providers still rely on the ELISA-Western blot diagnostic algorithm. We present a near misdiagnosis case with discordant test results and a lack of proper counseling. We point out the need for an assertive update of health care providers on diagnostic HIV-tests

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

INTRODUCTION

Misclassification errors have been reported in rapid diagnostic HIV tests (RDTs) in sub-Saharan African countries. These errors can lead to missed opportunities for prevention-of-mother-to-child-transmission (PMTCT), early infant diagnosis and adult HIV-prevention, unnecessary lifelong antiretroviral treatment (ART) and wasted resources. Few national estimates or systematic quantifications of sources of errors have been produced. We conducted a comprehensive assessment of possible sources of misclassification errors in routine HIV testing in Zimbabwe.

METHODS

RDT-based HIV test results were extracted from routine PMTCT programme records at 62 sites during national antenatal HIV surveillance in 2017. Positive- (PPA) and negative-percent agreement (NPA) for HIV RDT results and the false-HIV-positivity rate for people with previous HIV-positive results ("known-positives") were calculated using results from external quality assurance testing done for HIV surveillance purposes. Data on indicators of quality management systems, RDT kit performance under local climatic conditions and user/clerical errors were collected using HIV surveillance forms, data-loggers and a Smartphone camera application (7 sites). Proportions of cases with errors were compared for tests done in the presence/absence of potential sources of errors.

RESULTS

NPA was 99.9% for both pregnant women (N = 17224) and male partners (N = 2173). PPA was 90.0% (N = 1187) and 93.4% (N = 136) for women and men respectively. 3.5% (N = 1921) of known-positive individuals on ART were HIV negative. Humidity and temperature exceeding manufacturers' recommendations, particularly in storerooms (88.6% and 97.3% respectively), and premature readings of RDT output (56.0%) were common. False-HIV-negative cases, including interpretation errors, occurred despite staff training and good algorithm compliance, and were not reduced by existing external or internal quality assurance procedures. PPA was lower when testing room humidity exceeded 60% (88.0% vs. 93.3%; p = 0.007).

CONCLUSIONS

False-HIV-negative results were still common in Zimbabwe in 2017 and could be reduced with HIV testing algorithms that use RDTs with higher sensitivity under real-world conditions and greater practicality under busy clinic conditions, and by strengthening proficiency testing procedures in external quality assurance systems. New false-HIV-positive RDT results were infrequent but earlier errors in testing may have resulted in large numbers of uninfected individuals being on ART.

Venue-Based HIV Testing at Sex Work Hotspots to Reach Adolescent Girls and Young Women Living With HIV: A Cross-sectional Study in Mombasa, Kenya

BACKGROUND

We estimated the potential number of newly diagnosed HIV infections among adolescent girls and young women (AGYW) using a venue-based approach to HIV testing at sex work hotspots.

METHODS

We used hotspot enumeration and cross-sectional biobehavioral survey data from the 2015 Transition Study of AGYW aged 14-24 years who frequented hotspots in Mombasa, Kenya. We described the HIV cascade among young females who sell sex (YFSS) (N = 408) versus those young females who do not sell sex (YFNS) (N = 891) and triangulated the potential (100% test acceptance and accuracy) and feasible (accounting for test acceptance and sensitivity) number of AGYW that could be newly diagnosed through hotspot-based HIV rapid testing in Mombasa. We identified the profile of AGYW with an HIV in the past year using generalized linear mixed regression models.

RESULTS

N = 37/365 (10.1%) YFSS and N = 30/828 (3.6%) YFNS were living with HIV, of whom 27.0% (N = 10/37) and 30.0% (N = 9/30) were diagnosed and aware (P = 0.79). Rapid test acceptance was 89.3%, and sensitivity was 80.4%. There were an estimated 15,635 (range: 12,172-19,097) AGYW at hotspots. The potential and feasible number of new diagnosis was 627 (310-1081), and 450 (223-776), respectively. Thus, hotspot-based testing could feasibly reduce the undiagnosed fraction from 71.6% to 20.2%. The profile of AGYW who recently tested was similar among YFSS and YFNS. YFSS were 2-fold more likely to report a recent HIV test after adjusting for other determinants [odds ratio (95% confidence interval): 2.2 (1.5 to 3.1)].

CONCLUSION

Reaching AGYW through hotspot-based HIV testing could fill gaps left by traditional, clinic-based HIV testing services.

Utilization of Rapid Diagnostic Testing in sub-Saharan Africa: Challenges and Effects on HIV Prevention

The human immunodeficiency virus (HIV) remains a global threat to health. To prevent and control the disease caused by the virus, developed and developing countries continue to invest heavily in research and equipment so as to accurately detect the virus. The utilization of highly sensitive and effective rapid diagnostic tests (RDTs) have the potential to detect HIV in high-burden countries, especially those in sub-Saharan Africa (SSA). Yet, in SSA, challenges associated with HIV-RDT result inaccuracy, HIV misdiagnosis, poor tester capacity, and the improper storage of HIV-RDT kits have negatively impacted the benefits, and threaten to undermine HIV prevention. This paper focuses on the utilization of RDTs in HIV diagnosis in SSA, HIV-RDT challenges, and the effects of HIV-RDT challenges on HIV prevention. Subsequent to reviewing available literature, the authors found that although HIV-RDTs can negatively impact HIV-prevention efforts in SSA due to the likelihood of false positive HIV diagnoses, they generally provide quick results for people in resource poor settings, and do not require them to return to the testing sites to obtain their results. Obtaining accurate rapid HIV results means people who test positive can immediately seek care and take steps to prevent future transmission of the virus.

Challenges in estimating HIV prevalence trends and geographical variation in HIV prevalence using antenatal data: Insights from mathematical modelling

BACKGROUND

HIV prevalence data among pregnant women have been critical to estimating HIV trends and geographical patterns of HIV in many African countries. Although antenatal HIV prevalence data are known to be biased representations of HIV prevalence in the general population, mathematical models have made various adjustments to control for known sources of bias, including the effect of HIV on fertility, the age profile of pregnant women and sexual experience.

METHODS AND FINDINGS

We assessed whether assumptions about antenatal bias affect conclusions about trends and geographical variation in HIV prevalence, using simulated datasets generated by an agent-based model of HIV and fertility in South Africa. Results suggest that even when controlling for age and other previously-considered sources of bias, antenatal bias in South Africa has not been constant over time, and trends in bias differ substantially by age. Differences in the average duration of infection explain much of this variation. We propose an HIV duration-adjusted measure of antenatal bias that is more stable, which yields higher estimates of HIV incidence in recent years and at older ages. Simpler measures of antenatal bias, which are not age-adjusted, yield estimates of HIV prevalence and incidence that are too high in the early stages of the HIV epidemic, and that are less precise. Antenatal bias in South Africa is substantially greater in urban areas than in rural areas.

CONCLUSIONS

Age-standardized approaches to defining antenatal bias are likely to improve precision in model-based estimates, and further recency adjustments increase estimates of HIV incidence in recent years and at older ages. Incompletely adjusting for changing antenatal bias may explain why previous model estimates overstated the early HIV burden in South Africa. New assays to estimate the fraction of HIV-positive pregnant women who are recently infected could play an important role in better estimating antenatal bias.

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

BACKGROUND

Accurate HIV diagnosis is essential for appropriate patient care. Rapid tests (RTs) are considered key to HIV screening and management. Some studies have found RTs to be comparable with the ELISA test whilst others have reported lower sensitivity.

AIM AND STUDY DESIGN

The aim of this retrospective, descriptive study was to evaluate the sensitivity and specificity of the HIV 1/2/O Tri-line rapid test (HIV-TRT) device compared with ELISA.

METHOD

The study sample comprised 45 records of patients who tested for HIV using the HIV-TRT device and ELISA.

RESULTS

As compared with ELISA as the 100% gold standard, the sensitivity of the HIV-TRT was 80% (CI: 59%-93%) and specificity was 100% (CI: 83%-100%). ROC area of 0.9 at 95% CI was determined.

CONCLUSION

The low sensitivity of HIV-TRT is a concern, since HIV screening in South Africa makes use of RTs.

The potential for quality assurance systems to save costs and lives: the case of early infant diagnosis of HIV

OBJECTIVES

Scaling up of point-of-care testing (POCT) for early infant diagnosis of HIV (EID) could reduce the large gap in infant testing. However, suboptimal POCT EID could have limited impact and potentially high avoidable costs. This study models the cost-effectiveness of a quality assurance system to address testing performance and screening interruptions, due to, for example, supply stockouts, in Kenya, Senegal, South Africa, Uganda and Zimbabwe, with varying HIV epidemics and different health systems.

METHODS

We modelled a quality assurance system-raised EID quality from suboptimal levels: that is, from misdiagnosis rates of 5%, 10% and 20% and EID testing interruptions in months, to uninterrupted optimal performance (98.5% sensitivity, 99.9% specificity). For each country, we estimated the 1-year impact and cost-effectiveness (US$/DALY averted) of improved scenarios in averting missed HIV infections and unneeded HIV treatment costs for false-positive diagnoses.

RESULTS

The modelled 1-year costs of a national POCT quality assurance system range from US$ 69 359 in South Africa to US$ 334 341 in Zimbabwe. At the country level, quality assurance systems could potentially avert between 36 and 711 missed infections (i.e. false negatives) per year and unneeded treatment costs between US$ 5808 and US$ 739 030.

CONCLUSIONS

The model estimates adding effective quality assurance systems are cost-saving in four of the five countries within the first year. Starting EQA requires an initial investment but will provide a positive return on investment within five years by averting the costs of misdiagnoses and would be even more efficient if implemented across multiple applications of POCT.

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

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 short-cuts. 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.

Brief Report: Diagnostic Accuracy of Oral Mucosal Transudate Tests Compared with Blood-Based Rapid Tests for HIV Among Children Aged 18 Months to 18 Years in Kenya and Zimbabwe

Gaps persist in HIV testing for children who were not tested in prevention of mother-to-child HIV transmission programs. Oral mucosal transudate (OMT) rapid HIV tests have been shown to be highly sensitive in adults, but their performance has not been established in children.

Continuous quality monitoring in the field: an evaluation of the performance of the Fio Deki Reader™ for rapid HIV testing in South Africa

Background

Rapid diagnostic tests (RDTs) are a cornerstone of HIV diagnosis and rely on good quality processing and interpretation, particularly in the era of test and treat. The Deki Reader (Fio Corporation®, Toronto, Ontario, Canada) is a portable device designed specifically for analysing RDTs and was selected for evaluation in South Africa in the context of HIV RDT analysis.

Methods

This study consisted of a laboratory evaluation and two-part field evaluation of the Deki Reader v100, covering two RDT testing algorithms, and an evaluation of the continuous quality monitoring through the Fionet™ web portal. Based on user feedback from the field evaluation, the device underwent hardware and software redesign, and the Deki Reader v200 was evaluated in the laboratory. Ethics approval for this evaluation was obtained from the University of the Witwatersrand Human Research Ethics Committee: M150160.

Results

The intra- and inter-device laboratory precision of the Deki Reader v100 were 98.3 and 99.2% respectively, and 99.3 and 100% for the Deki Reader v200. The laboratory concordances compared to standard-of-care reporting were 99.5 and 98.0% for the two respective models, while sensitivity and specificity were 99.5 and 99.4% for the Deki Reader V100 and 100 and 93.1% for the Deki Reader V200 respectively. Screening and confirmatory concordances in the field were 99.3 and 96.5% under algorithm 1 and 99.7 and 100% under algorithm 2. Sensitivity and specificity for the field evaluation were 99.8 and 97.7%. Overall robustness of the device was acceptable and continuous quality monitoring through Fionet™ was feasible.

Conclusions

The Deki Reader provides an option for improved and reliable quality assessment for rapid diagnosis of HIV using RDTs to enhance the quality of healthcare at the point-of-care. However, the introduction of new RDTs and modification of current algorithms necessitates ongoing and agile RDT reader adjustments, which will require cost modelling to ensure sustainability of devices implemented into national HIV programs.

An overview of the quality assurance programme for HIV rapid testing in South Africa: Outcome of a 2-year phased implementation of quality assurance program

Objective

This is the first large-scale assessment of the implementation of HIV Rapid Test Quality Improvement Initiative in South Africa.

Methods

We used a quasi-experimental one group post-test only design. The intervention implemented starting April 2014 comprised health-care worker training on quality assurance (QA) of HIV rapid testing and enrolment of the facilities in proficiency testing (PT), targeting 2,077 healthcare facilities in 32 high HIV burden districts. Following the intervention, two consecutive rounds of site assessments were undertaken. The first, conducted after a median of 7.5 months following the training, included 1,915 facilities that participated in the QA training, while the second, conducted after a median of one-year following the first-round assessment included 517 (27.0%) of the 1,915 facilities. In both assessments, the Stepwise-Process-for-Improving-the-quality-of-HIV-Rapid-Testing (SPI-RT) checklist was used to score facilities’ performance in 7 domains: training, physical facility, safety, pre-testing, testing, post-testing and external quality assessment. Facilities’ level of readiness for national certification was assessed.

Result

Between 2016 and 2017, there were four PT cycles. PT participation increased from 32.4% (620/1,915) in 2016 to 91.5% (1,753/1,915) in 2017. In each PT cycle, PT results were returned by 76%–87% of facilities and a satisfactory result (>80%) was achieved by ≥95% of facilities. In the SPI-RT assessment, in round-one, 22.3% of facilities were close to or eligible for national certification—this significantly increased to 38.8% in round-two (P-value<0.001). The median SPI-RT score for the domains HIV pre-testing (83.3%) and post-testing (72.2%) remained the same between the two rounds. The median score for the testing domain increased by 5.6% (to 77.8%).

Conclusion

Facilities performance on the domains that are critical for accuracy of diagnosis (i.e. pre-testing, testing and post-testing) remained largely unchanged. This study provided several recommendations to improve QA implementation in South Africa, including the need to improve routine use of internal quality control for corrective actions.

Cost implications of HIV retesting for verification in Africa

INTRODUCTION

HIV misdiagnosis leads to severe individual and public health consequences. Retesting for verification of all HIV-positive cases prior to antiretroviral therapy initiation can reduce HIV misdiagnosis, yet this practice has not been not widely implemented.

METHODS

We evaluated and compared the cost of retesting for verification of HIV seropositivity (retesting) to the cost of antiretroviral treatment (ART) for misdiagnosed cases in the absence of retesting (no retesting), from the perspective of the health care system. We estimated the number of misdiagnosed cases based on a review of misdiagnosis rates, and the number of positives persons needing ART initiation by 2020. We presented the total and per person costs of retesting as compared to no retesting, over a ten-year horizon, across 50 countries in Africa grouped by income level. We conducted univariate sensitivity analysis on all model input parameters, and threshold analysis to evaluate the parameter values where the total costs of retesting and the costs no retesting are equivalent. Cost data were adjusted to 2017 United States Dollars.

RESULTS AND DISCUSSION

The estimated number of misdiagnoses, in the absence of retesting was 156,117, 52,720 and 29,884 for lower-income countries (LICs), lower-middle income countries (LMICs), and upper middle-income countries (UMICs), respectively, totaling 240,463 for Africa. Under the retesting scenario, costs per person initially diagnosed were: $40, $21, and $42, for LICs, LMICs, and UMICs, respectively. When retesting for verification is implemented, the savings in unnecessary ART were $125, $43, and $75 per person initially diagnosed, for LICs, LMICs, and UMICs, respectively. Over the ten-year horizon, the total costs under the retesting scenario, over all country income levels, was $475 million, and was $1.192 billion under the no retesting scenario, representing total estimated savings of $717 million in HIV treatment costs averted.

CONCLUSIONS

Results show that to reduce HIV misdiagnosis, countries in Africa should implement the WHO's recommendation of retesting for verification prior to ART initiation, as part of a comprehensive quality assurance program for HIV testing services.

Blameworthy bumping? Investigating nudge's neglected cousin

The realm of non-rational influence, which includes nudging, is home to many other morally interesting phenomena. In this paper, I introduce the term bumping, to discuss the category of unintentional non-rational influence. Bumping happens constantly, wherever people make choices in environments where they are affected by other people. For instance, doctors will often bump their patients as patients make choices about what treatments to pursue. In some cases, these bumps will systematically tend to make patients' decisions worse. Put another way: doctors will sometimes harm their patients by bumping them in systematic (although still unintentional) ways. I use the case of medical overuse, the provision of medical services where the likely harm outweighs the likely benefit to the patient, as a touchstone for arguing that doctors who systematically bump their patients towards harm can be blameworthy for their unwitting influence.

The impact and cost-effectiveness of community-based HIV self-testing in sub-Saharan Africa: a health economic and modelling analysis

INTRODUCTION

The prevalence of undiagnosed HIV is declining in Africa, and various HIV testing approaches are finding lower positivity rates. In this context, the epidemiological impact and cost-effectiveness of community-based HIV self-testing (CB-HIVST) is unclear. We aimed to assess this in different sub-populations and across scenarios characterized by different adult HIV prevalence and antiretroviral treatment programmes in sub-Saharan Africa.

METHODS

The synthesis model was used to address this aim. Three sub-populations were considered for CB-HIVST: (i) women having transactional sex (WTS); (ii) young people (15 to 24 years); and (iii) adult men (25 to 49 years). We assumed uptake of CB-HIVST similar to that reported in epidemiological studies (base case), or assumed people use CB-HIVST only if exposed to risk (condomless sex) since last HIV test. We also considered a five-year time-limited CB-HIVST programme. Cost-effectiveness was defined by an incremental cost-effectiveness ratio (ICER; cost-per-disability-adjusted life-year (DALY) averted) below US$500 over a time horizon of 50 years. The efficiency of targeted CB-HIVST was evaluated using the number of additional tests per infection or death averted.

RESULTS

In the base case, targeting adult men with CB-HIVST offered the greatest impact, averting 1500 HIV infections and 520 deaths per year in the context of a simulated country with nine million adults, and impact could be enhanced by linkage to voluntary medical male circumcision (VMMC). However, the approach was only cost-effective if the programme was limited to five years or the undiagnosed prevalence was above 3%. CB-HIVST to WTS was the most cost-effective. The main drivers of cost-effectiveness were the cost of CB-HIVST and the prevalence of undiagnosed HIV. All other CB-HIVST scenarios had an ICER above US$500 per DALY averted.

CONCLUSIONS

CB-HIVST showed an important epidemiological impact. To maximize population health within a fixed budget, CB-HIVST needs to be targeted on the basis of the prevalence of undiagnosed HIV, sub-population and the overall costs of delivering this testing modality. Linkage to VMMC enhances its cost-effectiveness.

Optimizing HIV testing services in sub-Saharan Africa: cost and performance of verification testing with HIV self-tests and tests for triage

INTRODUCTION

Strategies employing a single rapid diagnostic test (RDT) such as HIV self-testing (HIVST) or "test for triage" (T4T) are proposed to increase HIV testing programme impact. Current guidelines recommend serial testing with two or three RDTs for HIV diagnosis, followed by retesting with the same algorithm to verify HIV-positive status before anti-retroviral therapy (ART) initiation. We investigated whether clients presenting to HIV testing services (HTS) following a single reactive RDT must undergo the diagnostic algorithm twice to diagnose and verify HIV-positive status, or whether a diagnosis with the setting-specific algorithm is adequate for ART initiation.

METHODS

We calculated (1) expected number of false-positive (FP) misclassifications per 10,000 HIV negative persons tested, (2) positive predictive value (PPV) of the overall HIV testing strategy compared to the WHO recommended PPV ≥99%, and (3) expected cost per FP misclassified person identified by additional verification testing in a typical low-/middle-income setting, compared to the expected lifetime ART cost of $3000. Scenarios considered were as follows: 10% prevalence using two serial RDTs for diagnosis, 1% prevalence using three serial RDTs, and calibration using programmatic data from Malawi in 2017 where the proportion of people testing HIV positive in facilities was 4%.

RESULTS

In the 10% HIV prevalence setting with a triage test, the expected number of FP misclassifications was 0.86 per 10,000 tested without verification testing and the PPV was 99.9%. In the 1% prevalence setting, expected FP misclassifications were 0.19 with 99.8% PPV, and in the Malawi 2017 calibrated setting the expected misclassifications were 0.08 with 99.98% PPV. The cost per FP identified by verification testing was $5879, $3770, and $24,259 respectively. Results were sensitive to assumptions about accuracy of self-reported reactive results and whether reactive triage test results influenced biased interpretation of subsequent RDT results by the HTS provider.

CONCLUSIONS

Diagnosis with the full algorithm following presentation with a reactive triage test is expected to achieve PPV above the 99% threshold. Continuing verification testing prior to ART initiation remains recommended, but HIV testing strategies involving HIVST and T4T may provide opportunities to maintain quality while increasing efficiency as part of broader restructuring of HIV testing service delivery.

Re-reading of OraQuick HIV-1/2 rapid antibody test results: quality assurance implications for HIV self-testing programmes

INTRODUCTION

Scale-up of HIV self-testing (HIVST) will play a key role in meeting the United Nation's 90-90-90 targets. Delayed re-reading of used HIVST devices has been used by early implementation studies to validate the performance of self-test kits and to estimate HIV positivity among self-testers. We investigated the stability of results on used devices under controlled conditions to assess its potential as a quality assurance approach for HIVST scale-up.

METHODS

444 OraQuick® HIV-1/2 rapid antibody tests were conducted using commercial plasma from two HIV-positive donors and HIV-negative plasma (high-reactive n = 148, weak-reactive n = 148 and non-reactive n = 148) and incubated them for six months under four conditions (combinations of high and low temperatures and humidity). Devices were re-read daily for one week, weekly for one subsequent month and then once a month by independent readers unaware of the previous results. We used multistage transition models to investigate rates of change in device results, and between storage conditions.

RESULTS AND DISCUSSION

There was a high incidence of device instability. Forty-three (29%) of 148 initially non-reactive results became false weak-reactive results. These changes were observed across all incubation conditions, the earliest on Day 4 (n = 9 kits). No initially HIV-reactive results changed to a non-reactive result. There were no significant associations between storage conditions and hazard of results transition. We observed substantial statistical agreement between independent re-readers over time (agreement range: 0.74 to 0.96).

CONCLUSIONS

Delayed re-reading of used OraQuick® HIV-1/2 rapid antibody tests is not currently a valid methodological approach to quality assurance and monitoring as we observed a high incidence (29%) of true non-reactive tests changing to false weak-reactive and therefore its use may overestimate true HIV positivity.

Low and Decreasing Prevalence and Rate of False Positive HIV Diagnosis - Chókwè District, Mozambique, 2014-2017

In 2017, rapid human immunodeficiency virus (HIV) testing services enabled the HIV diagnosis and treatment of approximately 15.3 million persons with HIV infection in sub-Saharan Africa with life-saving antiretroviral therapy (ART) (1). Although suboptimal testing practices and misdiagnoses have been reported in sub-Saharan Africa and elsewhere, trends in population burden and rate of false positive HIV diagnosis (false diagnosis) have not been reported (2,3). Understanding the population prevalence and trends of false diagnosis is fundamental for guiding rapid HIV testing policies and practices. To help address this need, CDC analyzed data from 57,655 residents aged 15-59 years in the Chókwè Health and Demographic Surveillance System (CHDSS) in Mozambique to evaluate trends in the rate (the percentage of false diagnoses among retested persons reporting a prior HIV diagnosis) and population prevalence of false diagnosis. From 2014 to 2017, the observed rate of false diagnosis in CHDSS decreased from 0.66% to 0.00% (p<0.001), and the estimated population prevalence of false diagnosis decreased from 0.08% to 0.01% (p = 0.0016). Although the prevalence and rate of false diagnosis are low and have decreased significantly in CHDSS, observed false diagnoses underscore the importance of routine HIV retesting before ART initiation and implementation of comprehensive rapid HIV test quality management systems (2,4,5).