Head-to-head comparison of accuracy of a rapid point-of-care HIV test with oral versus whole-blood specimens: a systematic review and meta-analysis

Summary

Background

The focus on prevention strategies aimed at curbing the HIV epidemic is growing, and therefore screening for HIV has again taken centre stage. Our aim was to establish whether a convenient, non-invasive, HIV test that uses oral fluid was accurate by comparison with the same test with blood-based specimens.

Methods

We did a systematic review and meta-analysis to compare the diagnostic accuracy of a rapid HIV-antibody-based point-of-care test (Oraquick advance rapid HIV-1/2, OraSure Technologies Inc, PA, USA) when used with oral versus blood-based specimens in adults. We searched five databases of published work and databases of five key HIV conferences. Studies we deemed eligible were those focused on adults at risk of HIV; we excluded studies in children, in co-infected populations, with self-reported inferior reference standards, and with incomplete reporting of key data items. We assessed the diagnostic accuracy of testing with oral and blood-based specimens with bivariate regression analysis. We computed positive predictive values (PPVs) in high-prevalence and low-prevalence settings with Bayesian methods.

Findings

In a direct head-to-head comparison of studies, we identified a pooled sensitivity about 2% lower in oral (98·03%, 95% CI 95·85–99·08) than in blood-based specimens (99·68%, 97·31–99·96), but similar specificity (oral 99·74%, 99·47–99·88; blood 99·91%, 99·84–99·95). Negative likelihood ratios were small and similar (oral 0·019, 0.009–0·040; blood 0·003, 0·001–0·034), but positive likelihood ratios differed (oral 383·37, 183·87–799·31; blood 1105·16, 633·14–2004·37). Although in high-prevalence settings PPVs were similar (oral 98·65%, 95% credible interval 85·71–99·94; blood 98·50, 93·10–99·79), in low-prevalence settings PPVs were lower for oral (88·55%, 77·31–95·87) than blood (97·65%, 95·48–99·09) specimens.

Interpretation

Although Oraquick had a high PPV in high-prevelence settings in oral specimens, the slightly lower sensitivity and PPV in low-prevalence settings in oral specimens should be carefully reviewed when planning worldwide expanded initiatives with this popular test.

Funding

Canadian Institutes for Health Research (CIHR KRS 102067).

Introduction

In 2004, a rapid HIV-antibody-based point-of-care test (Oraquick advance rapid HIV-1/2, OraSure Technologies Inc, PA, USA), initially approved for finger-stick, whole-blood, and plasma specimens, was approved by the US Food and Drug Administration (FDA) as a Clinical Laboratory Improvement Amendments waived test for use with specimens of oral mucosal transudate. Since 2006, with the widespread expansion of HIV testing in the USA, and with the possible expansion of home-based and new supervised self-testing initiatives in sub-Saharan Africa, this HIV test has become one of the most popular point-of-care tests based on oral specimens.1, 2, 3 It is more acceptable to patients because of its non-invasive and pain-free specimen collection and its rapid turnaround time.4, 5, 6 In Kenya and Uganda, an increased acceptance and preference for this test has helped improve the uptake of home-based HIV-testing initiatives.7, 8 The Kenyan Government also announced an expansion of bold and controversial self-testing initiatives for HIV, and is reviewing the possible approval of oral tests. Self-testing initiatives are also relevant for southern Africa, a region that has remained the epidemiological locus of the epidemic; countries such as Botswana, Lesotho, Mozambique, South Africa, Swaziland, Zambia, and Zimbabwe are focused on scaling up alternative HIV-screening programmes.

Oraquick is also being considered for potential use as an over-the-counter test in the USA and in many sub-Saharan countries. This move might revolutionise HIV testing by offering a proactive testing option to people who, because of stigma, do not wish to attend public health centres for testing. Hopefully, offering a confidential testing option will bring an end to the stigmatisation associated with HIV testing.⁹ Although performance data are available on this test from the USA, there has not been a review of its worldwide accuracy. With optimistic developments in HIV aimed at eradicating infection, worldwide expansion of HIV-testing programmes has taken centre stage because testing is the cornerstone of care and treatment.¹⁰ With self-testing initiatives imminent, programme planners and policy makers are keen to know the relative accuracy and performance of Oraquick in oral versus blood specimens, to decide on the optimum testing algorithm.

So far, worldwide comparative data on this test have not been critically synthesised and the effect of prevalence on test accuracy has not been reviewed. This exploration is important because countries with low prevalence for HIV might consider the possible expansion of HIV-screening initiatives in the future. With a view to generating the evidence base for policy recommendations, we aimed to review worldwide evidence of this popular point-of-care test.