A new blood test can diagnose HIV as soon as 14 days after infection, thus reducing the length of the “window period” between infection and when the virus can be detected.  Abbott's new Architect HIV Ag/Ab Combo assay detects HIV sooner because it looks for HIV antibodies, which can take weeks to appear, and antigens—fragments of HIV itself—which become detectable within days of infection.

Though Architect finds HIV earlier, its testing process takes longer than the 20-minute oral swab test (which detects HIV four to six weeks post transmission). Furthermore, results may not be available until the next day.

Architect will be particularly useful in high-risk groups, such as gay men and people of color, as studies have found rapid oral swab tests have missed up to 10 percent of new infections.

“[Architect] is the first of what we expect to be several combo tests” to be approved in coming years, says Bernard Branson, MD, who oversees HIV testing at the U.S. Centers for Disease Control and Prevention.

Meanwhile, the oral swab test will likely remain more popular. Most HIV infections are not recent, and unlike Architect, oral-swab testing doesn't involve blood. Nor does it rely on test takers to be brave enough to come back for their results.

If you think you've been exposed to HIV in the past six weeks, ask your doc to test you using Architect. If it's been longer than that, go with the oral-swab test.