The performance of the Alere HIV combo point-of-care test on stored serum samples; useful for detection of early HIV-1 infections?

INTRODUCTION: The Alere HIV-1/2 Antigen/Antibody Combo point-of-care test is a commercially available 4th-generation rapid test for the diagnosis of HIV infection, including acute infection. We evaluated the sensitivity of this test in samples from patients with acute, recent or chronic HIV-1 infection.

METHODS: A validation of the test was performed using 89 HIV-positive serum samples collected in 2008-2016, that were stored at -20°C. Twenty-three samples were only p24-positive (acute infection); 49 samples were antibody-positive and p24-positive (recent infection); 17 samples were only antibody-positive (chronic infection). HIV infection was confirmed by standard-of-care assays and PCR. Samples came from patients attending an outpatient clinic for STDs at the Public Health Department and from patients within the Erasmus Medical Center, Rotterdam, the Netherlands.

RESULTS: The overall sensitivity of the test for diagnosing HIV infection based on detection of p24 antigen and/or antibodies was 92% (95% CI 86% to 98%) (82/89). In acute sera with only p24 antigen positivity, the sensitivity of the test decreased to 65% (95% CI 46% to 85%) (15/23). When both antibody and antigen testing were positive, the p24 sensitivity was only 24% (95% CI 12% to 36%) (12/49), but in these sera the final test result was positive in all sera (49/49) due to the positive antibody component.

CONCLUSIONS: In a laboratory setting, this test has an overall sensitivity of 92% to detect any stage of HIV-1 infection using sera specimens. It performs relatively well in detecting early HIV and may be beneficial as an initial screening in patients with a recent exposure to HIV. Additional testing in a laboratory setting remains mandatory as a proportion of acute HIV-1 infections are missed with this test.