How Reliable Are In-Home HIV Tests?

Despite High Sensitivity Levels, False Negatives Pose Concerns

Photo Credit: OraQuick

In July 2012, the U.S. Food and Drug Administration (FDA) granted approval to the OraQuick In-Home HIV Test, providing consumers with the first, over-the-counter oral HIV test able to provide confidential results in as little as 20 minutes. The FDA approval was welcomed by many community-based organizations, which have long cited the benefits of in-home testing at a time when 20% of the 1.2 million Americans infected with HIV are fully unaware of their status.

Chief among the arguments in support of in-home testing:

  • Many public clinics in the U.S. are either understaffed or overtaxed, causing those who may want or need testing to stay away. In-home testing can help overcome this hurdle, providing those most at risk with a greater sense of autonomy, control and confidentiality.
  • In their approval of the product, the FDA stated that in-home testing "will contribute measurably... by helping more infected individuals to become aware of their HIV status and thereby reducing HIV transmission."
  • A 24-hour hotline with trained staff will help ensure that the product is used correctly; that users understand the limitations of the test (including the so-called window period), and that those who receive a positive result are referred to a nearby clinic or doctor's office.

As of September 2013, the OraQuick manufacturers reported that "more than 200,000 individuals now know their HIV status" as a result of the product, with industry analysts predicting an uptake in sales as consumer awareness increases.

Yet despite the apparent benefits of the tests, a number of studies have highlighted concerns about the in-home strategy, questioning the product's real-world accuracy, as well as its impact on patient care and risk behaviors.

How Accurate Are In-Home HIV Tests?

According to the FDA report, the OraQuick Rapid In-Home Test is not only safe and easy-to-use, but offers a sensitivity and specificity of roughly 95%—slightly less than the 99.3% and 99.8% seen with point-of-care kits used by physicians and clinics.

However, unlike point-of-care tests, the in-home version is known to have a false negative rate of around 7%, meaning that one out of every 12 tests will deliver an incorrect "all clear sign." While this doesn't necessarily undermine the product's viability, it does bring into question the real-world accuracy of the tests given the likelihood of product misuse and/or premature HIV testing.

One study conducted in 2013 by the University of California, San Francisco concluded that fourth-generation rapid oral tests like OraQuick were able to correctly identify 86% of HIV-positive cases, significantly less than what was seen in clinical trials. More concerning yet was the fact that the product had only 54% accuracy in confirming serostatus during the acute (early) stage of infection.

With increasing evidence that intervention at the time of acute infection may decrease the development of latent reservoirs where HIV is known to hide (or "persist") for decades, the need for tests with high degrees of sensitivity has become an imperative—particularly in light of the call for universal testing and treatment both domestically and globally.

While the OraQuick package insert does forewarn users about the risk of premature testing, greater emphasis will need to be placed on product improvement, rather than consumer awareness, to overcome these statistical shortcomings.

Will In-Home Testing Improve Patient Linkage to Care?

From a policy standpoint, one of the major aims of in-home testing is to increase the number of patients actively linked to HIV care in the U.S. It's an ambitious goal given that only 437,000 of the 874,000 Americans diagnosed with HIV have accessed medical treatment, according to research published by the U.S. Centers for Disease Control and Prevention.

While most research indicates a widespread public acceptance of in-home testing, there is little actual data to determine whether patients are linking themselves to care as a result of these tests. Although several studies in Africa have shown an increase in linkage after in-home testing—by as much as 300% in some cases—these were conducted after a pre-test counseling visit was performed by a trained professional.

With no such strategy employed in the U.S., might the same be expected here or, more concisely perhaps, does it actually make a difference?

Most agree that it would be difficult to fully assess given many testing centers do not report outcomes to linkage to care after testing. What we do know, however, is that unsupported HIV testing, in and of itself, falls short in a number of key areas—most significantly in the reduction of high risk behaviors seen in those who test negative.

In a study conducted by Columbia University's Mailman School of Public Health, 5,000 randomly assigned patients received either an informational sheet or a brief counseling session in advance of a rapid test. After 12 months, the patients were reassessed.  Alarmingly, 11.1% of the information-only group had acquired an STD, while nearly the same number of patients (12.3%) acquired an STD after being provided brief counseling. The findings were consistent in all of the nine clinics used after taking into account the patient's age, gender and ethnicity.

Computer modelling by the HIV/STD Program of Public Health, Seattle & King County further supported this conclusion, suggesting that in-home testing may increase HIV prevalence among men who have sex with men (MSM) from a baseline of 18.6% to anywhere between 22.5% to 27.5%.

While none of this is meant to suggest that in-home HIV testing will undermine public health efforts, it does reinforce the need for greater clarification of the benefits and limitations of in-home HIV testing, both to the consumer and health policy makers.

Sources:

U.S. Food and Drug Administration (FDA). "First Rapid Home-Use HIV Kit Approved for Self-Testing." FDA Consumer Health Information. Silver Spring, MD; July 2012. Document: UCM311690.

The Wall Street Journal. "OraQuick(R) In-Home HIV Test Launches New Targeted Campaign Strategy -- "Life. As we know it.(TM)" Encourages HIV Testing Among High Risk Groups." Press release issued September 30, 2013.

Pilcher, C.; Louie, B.; Facente, S.; et al. "Performance of Rapid Point-of-Care and Laboratory Tests for Acute and Established HIV Infection in San Francisco." PLOS | One. December 12, 2013; DOI: 10.1371/journal.pone.0080629.

Pai, N.; Sharma, J.; Shivkumar, S; et al. "Supervised and Unsupervised Self-Testing for HIV in High- and Low-Risk Populations: A Systematic Review." PLOS|One. April 2, 2013; DOI: 10.1371/journal.pmed.1001414.

Macpherson, P.;  et al. "Home assessment and initiation of ART following HIV self-testing: a cluster-randomized trial to improve linkage to ART in Blantyre, Malawi." 20th Conference on Retroviruses and Opportunistic Infections (CROI); Atlanta, Georgia; Abstract 95LB, 2013.

Metsch, L.; Feaster, D.; Gooden, L.; et al. "Effect of risk-reduction counseling with rapid HIV testing on risk of acquiring sexually transmitted infections: the AWARE randomized clinical trial." Journal of the American Medical Association. October 23, 2013; 310(16):1701-1710.

Katz, D.; Cassels, S.; and Sketler, J. "Replacing Clinic-Based Tests With Home-Use Tests May Increase HIV Prevalence Among Seattle Men Who Have Sex With Men: Evidence From a Mathematical Model." Sexually Transmitted Diseases. January 2014; 41(1):2-9.

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