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Four point-of-care (POC) tests for HIV that use unprocessed specimens are able to detect HIV infections with high specificity and sensitivity, according to the results of a study published in the Journal of Clinical Virology.
Currently in the United States, approximately 14.2% of people living with HIV are undiagnosed and, as a result, are not receiving appropriate treatment and care. Diagnosing HIV infections in a variety of settings requires consideration of both logistic feasibility and test performance. Though more sensitive laboratory-based testing is not feasible, the Centers for Disease Control and Prevention (CDC) has emphasized the importance of using POC HIV tests to identify HIV infections in high-risk, hard-to-reach populations because the tests are easy to use and provide fast results. Although the US Food and Drug Administration has approved several POC tests to identify HIV infections earlier, many of the newer approved tests have not been evaluated in real-world settings or in persons receiving HIV pre-exposure prophylaxis (PrEP). Therefore, this study evaluated the sensitivity and specificity of 4 POC HIV tests using unprocessed whole blood and oral fluid specimens.
In total, 1004 participants were recruited and provided data over a total of 1256 visits. Data were analyzed from participants who were tested with 4 POC tests using fresh whole blood (Chembio DDP HIV-1/2, Determine HIV-1/2 Ag/Ab Combo, OraQuick ADVANCE Rapid HIV-1/2 Antibody Test, and INSTI HIV-1/HIV-2 Rapid Antibody Test) and 2 POC tests using fresh oral fluid (Chembio DDP HIV-1/2 and OraQuick ADVANCE Rapid HIV-1/2 Antibody Test). HIV status determination was based on the CDC-recommended laboratory-based HIV testing algorithm.
Of the study cohort, 179 participants had HIV infection, of whom 12 participants had early HIV infection and 6 participants had acute HIV infection. A total of 120 patients with HIV reported receiving antiretroviral therapy (ART).
The sensitivity of POC tests that used whole blood ranged from 95.53% to 97.21% and there were no differences observed across tests (P >.05 for all comparisons). When specimens of participants with acute HIV were excluded, sensitivity estimates were higher. However, the POCs accurately identified 3 participants with acute HIV (50%): 1 by the Determine test and 2 by the INSTI test. When testing specimens of those on ART, the sensitivities of the DDP test and OraQuick test were significantly lower when performed on oral fluid compared with whole blood.
The specificity was high for all tests, ranging from 99.44% to 100.00%. However, compared with DPP of oral fluid, DDP of whole blood, and OraQuick of whole blood, the Determine test had a significantly lower specificity (P =.031).
Use of PrEP did not affect test specificity, but because ART compromised the sensitivity of oral fluid tests, the concept of not using POC tests on people receiving PrEP was reinforced. In total, there were 9 false-positive results, but no specimen tested false positive on more than 1 test.
It should be acknowledged by healthcare organizations that POC HIV tests have limitations and a plan to manage false results should be in place. Overall, the study authors concluded that, “These POC tests displayed relatively high sensitivity and specificity using unprocessed specimens suggesting their effectiveness in identifying HIV infections whenever laboratory-based testing is not feasible.”
Reference
Chavez PR, Bradley HM, Wesolowski LG, et al. Performance evaluation of four point-of-care HIV tests using unprocessed specimens [published online January 16, 2020]. J Clin Vir. doi: 10.11016/j.jcv.2020.104282
