5 Facts About the Alere Determine HIV Combo Test

Combination HIV Test Considered a Preferred Option by the CDC

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HIV-1 rapid fingerstick test. Image courtesy Alere, Inc.

When the U.S. Food and Drug Administration approved the Alere Determine HIV-1/2 Ag/Ab Combo test on August 9, 2013, it was universally welcomed by both health providers and policy makers alike. It wasn't  that weren't already point-of-care tools available to test for HIV-1 or HIV-2, or ones that could separately detect HIV antigens or antibodies.

Beyond the sheer convenience of an all-in-one application, the Alere Determine Combo stood head and shoulders above previous generation tests, offering higher levels of sensitivity, specificity and speed.

So effective are these tests that they are today among the two assays (alongside the Abbott ARCHITECT HIV Ag/Ab Combo) recommended by the Centers for Disease Control and Prevention as the preferred options for HIV detection in the U.S.

Here are 5 facts you should know about the Alere Determine Combo:

1. The Determine Combo is not an over-the-counter HIV test.

Unlike the OraQuick In-Home Oral HIV Test, the Determine Combo is a simple finger-prick blood test that is administered only at qualified testing centers.While the OraQuick can provide confidential home testing in as little as 20 minutes, it currently has a false negative rate of 15% (or roughly one out of seven tests).

2. Testing for HIV antigens is generally faster than testing for antibodies.

Antigens are the foreign substances that cause the body to produce immune antibodies. Therefore, as a rule, a rapid test for HIV antigens provide faster results than an antibody test.

In the case of Determine Combo, we're talking results in 12-26 days versus 20-45 days for an antibody-based test.

3. The current Determine Combo tests only for HIV-1 antigens, not HIV-2 antigens.

Neither does it distinguish between HIV-1 and HIV-2 antibodies. All this really means is that those who have an HIV-2 infection (which is found primarily in West Africa) may have a slightest higher incidence of inconclusive test results.

4. While the Determine Combo is accurate, it is still not an endpoint test.

Even if a person does test positive for both HIV antigens and HIV antibodies, a confirmatory HIV-1 nucleic acid test (NAT) still needs to be performed. The HIV-1 NAT is able to detect viral RNA with high levels of accuracy in as little as 1-2 weeks post-infection.

5. The Detemine Combo falls short during acute infection.

Despite an antigen sensitivity of only 86%, the combination of antibody/antigen testing increases overall sensitivity to well over 99%, this according to updated algorithms issued by the CDC.

However, it didn't perform as well in persons with recent (acute) infection. According to a research from the University of California, San Francisco, the Determine Combo was was able to identify only half of acute infections and  usually only did so when the patient's viral load was well over 500,000 copies/mL. 

By contrast, the lab-based ARCHITECT combination antigen/antibody test performed the best of possible assays.

With an estimated specificity of between 99.1% and a specificity of 100%, the tests were able to identify nearly 90% of acute infections.

Sources:

U.S. Food and Drug Administration (FDA). "FDA approve first rapid diagnostic test to detect both HIV-1 antigen and HIV-1/2 antibodies." Silver Spring, Maryland; press release issued August 8, 2013.

Branson, B.; Owen, S.; Wesolowski, M.; et al. "Laboratory Testing for the Diagnosis of HIV Infection: Updated Recommendations." U.S. Centers for Disease Control and Prevention (CDC). Atlanta, Georgia; released June 27, 2014.

Pilcher, D.; 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.

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