Determination of HIV Status in African Adults With Discordant HIV Rapid Tests

HIV serologically indeterminate individuals: Future HIV status and risk factors

BACKGROUND

Indeterminate HIV test results are common, but little is known about the evolution of indeterminate serology and its sociodemographic and behavioral correlates. We assessed future HIV serological outcomes for individuals with indeterminate results and associated factors in Rakai, Uganda.

METHODS

115,944 serological results, defined by two enzyme immunoassay (EIAs), among 39,440 individuals aged 15-49 years in the Rakai Community Cohort Study were assessed. Indeterminate results were defined as contradictory EIAs. Modified Poisson regression models with generalized estimating equations were used to assess prevalence ratios (PRs) of subsequent HIV serological outcomes and factors associated with HIV indeterminate results.

RESULTS

The prevalence of HIV serologically indeterminate results was 4.9%. Indeterminate results were less likely among women than men (adjPR 0.76, 95% CI 0.71,0.81), in unmarried participants than married participants (adjPR 0.92, 95% CI 0.85,99), and in individuals with primary (adjPR 0.90, 95% CI 0.80,1.02), secondary (adjPR 0.83, 95% CI 0.73,0.96) and post-secondary (adjPR 0.75, 95% CI 0.60,0.94) education, relative to no education. The proportions of persons with indeterminate results progressing to HIV positive, negative or indeterminate results in subsequent visits was 5%, 71% and 24%, respectively.

CONCLUSION

HIV serologically indeterminate results were associated with gender and marital status. HIV surveillance programs should develop a protocol for reporting individuals with mixed or persistently indeterminate HIV results on multiple follow-up visits. Most indeterminate results became HIV-negative over time, but follow-up is still needed to detect positive serologies.

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.

Identification of misdiagnosed HIV clients in an Early Access to ART for All implementation study in Swaziland

Introduction: Rapid diagnostic testing has made HIV diagnosis and subsequent treatment more accessible. However, multiple factors, including improper implementation of testing strategies and clerical errors, have been reported to lead to HIV misdiagnosis. The World Health Organization has recommended HIV retesting prior to antiretroviral therapy (ART) initiation which has become pertinent with scaling up of Early Access to ART for All (EAAA). In this analysis, misdiagnosed clients are identified from a subgroup of clients enrolled in EAAA implementation study in Swaziland.

Methods: The subgroup to assess misdiagnosis was identified from enrolled EAAA study clients, who had an undetectable viral load prior to ART initiation between September 1, 2014 and May 31, 2016. One hundred and five of 2533 (4%) clients had an undetectable viral load prior to initiation to ART (pre-ART). The HIV status of clients was confirmed using the Determine HIV 1/2 and Uni-Gold HIV 1/2 rapid tests performed serially as recommended by the national testing algorithm. The status of clients on ART was additionally confirmed by fourth-generation HIV Ag/Ab combo tests, Architect and Genscreen Ultra.

Results: Fourteen of the 105 (13%) clients were false positive (HIV negative) on confirmation testing, of whom five (36%) were still in pre-ART care, while nine (64%) were in ART care. Overall, proportion of false positive was 0.6% (14/2533). The false-positive clients had a median CD4 of 791 cells/ml (interquartile range (IQR): 628, 967) compared to 549 cells/ml (IQR: 387, 791) for true positives (HIV positive) (p = 0.0081) and were nearly 20 years older (p = 0.0008).

Conclusions: Overall 0.6% of all enrolled EAAA clients were misdiagnosed, and 64% of misdiagnosed clients were initiated on ART. With adoption of EAAA guidelines by national governments, ART initiation regardless of immunological criteria, strengthening of proficiency testing and adoption of retesting prior to ART initiation would allow identification of misdiagnosed clients and further reduce potential of initiating misdiagnosed clients on ART.

Brief Report: Impact of Early Antiretroviral Therapy on the Performance of HIV Rapid Tests and HIV Incidence Assays

BACKGROUND

Antiretroviral therapy (ART) can downregulate antibody responses to HIV infection. We evaluated the impact of early vs. delayed ART on the performance of HIV diagnostic and incidence assays.

METHODS

Samples were obtained from 207 participants in the HPTN 052 trial, who were stably suppressed on ART for ≥4 years [Malawi sites; pre-ART CD4 cell count 350-550 cells/mm (early ART arm, N = 180) or <250 cells/mm or an AIDS-defining illness (delayed ART arm, N = 27)]. Samples were tested with 2 HIV rapid tests and 2 HIV incidence assays; selected samples were also tested with two fourth-generation immunoassays and a Western blot (WB) assay. A pre-ART sample was analyzed if the follow-up sample had a false-negative or weakly-reactive rapid test result, or had an incidence assay result indicative of recent infection (false-recent result).

RESULTS

Ten (4.8%) samples had a nonreactive or weakly-reactive rapid test result (7/180 early ART arm, 3/27 delayed ART arm, P = 0.13); one sample had nonreactive fourth-generation assay results and 3 had indeterminate WBs. Forty (18.9%) samples had a false-recent incidence assay result; 16 (7.8%) had false-recent results with both incidence assays. Baseline samples had stronger rapid test and WB bands, higher fourth-generation assay signal-to-cutoff values, and fewer HIV incidence assay results indicative of recent infection.

CONCLUSIONS

False-negative/weakly-reactive HIV rapid tests and false-recent HIV incidence assay results were observed in virally-suppressed individuals, regardless of pre-ART CD4 cell count. Downregulation of the antibody response to HIV infection in the setting of ART may impact population-level surveys of HIV prevalence and incidence.

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

INTRODUCTION

In accordance with global testing and treatment targets, many countries are seeking ways to reach the "90-90-90" goals, starting with diagnosing 90% of all people with HIV. Quality HIV testing services are needed to enable people with HIV to be diagnosed and linked to treatment as early as possible. It is essential that opportunities to reach people with undiagnosed HIV are not missed, diagnoses are correct and HIV-negative individuals are not inadvertently initiated on life-long treatment. We conducted this systematic review to assess the magnitude of misdiagnosis and to describe poor HIV testing practices using rapid diagnostic tests.

METHODS

We systematically searched peer-reviewed articles, abstracts and grey literature published from 1 January 1990 to 19 April 2017. Studies were included if they used at least two rapid diagnostic tests and reported on HIV misdiagnosis, factors related to potential misdiagnosis or described quality issues and errors related to HIV testing.

RESULTS

Sixty-four studies were included in this review. A small proportion of false positive (median 3.1%, interquartile range (IQR): 0.4-5.2%) and false negative (median: 0.4%, IQR: 0-3.9%) diagnoses were identified. Suboptimal testing strategies were the most common factor in studies reporting misdiagnoses, particularly false positive diagnoses due to using a "tiebreaker" test to resolve discrepant test results. A substantial proportion of false negative diagnoses were related to retesting among people on antiretroviral therapy. Conclusions HIV testing errors and poor practices, particularly those resulting in false positive or false negative diagnoses, do occur but are preventable. Efforts to accelerate HIV diagnosis and linkage to treatment should be complemented by efforts to improve the quality of HIV testing services and strengthen the quality management systems, particularly the use of validated testing algorithms and strategies, retesting people diagnosed with HIV before initiating treatment and providing clear messages to people with HIV on treatment on the risk of a "false negative" test result.