Ask the Doc: The Hidden Risks of HIV Testing

In this installment of Ask the Doc, Dr. Howard Scheiner looks at what you really need to do to keep yourself healthy and disease-free.

For those who don't like the doctor's office, are at-home HIV tests good enough? And how often do you really need to do them? The doc will give you the low-down on just how accurate the tests are, and which ones to take to get the true results of your status.

Also, with HIV to deal with, how worried do I have to be about other STDs? Won't a shot of penicillin take care of them? Dr. S will give you the straight talk on HIV and STDs, including the high rates of infection among MSM.

Ask The Doc -- you just might be surprised at the answers you get!

Home HIV Testing

Q. Dear Doc, I take an at-home HIV test every six months to make sure I'm not infected. This means I'm covered, right?

A. As with so many things, the answer is yes and no. If you are still negative then home testing, using the OraQuick rapid test on saliva is likely to give you an accurate result with 99.9 percent accuracy. That's the yes. That is what is known as the specificity of the test. There are almost no false-positives. HIV-negative people correctly receive HIV-negative results.

Unfortunately, if you have recently become HIV-positive, the result is not as accurate. If you have converted to positive in the last one to three months before you have retested, there is a good chance your home test will miss it. A large study out of San Francisco showed that if the test used only detects HIV antibodies (OraQuick and all first- through third- generation lab tests), most acute (recent) HIV infections are missed.

Moreover, the OraQuick rapid test also missed established infections when testing saliva samples-getting only an 86.6 percent accuracy. All individuals with acute HIV infection and one in twenty individuals with established HIV infection were given negative results that were incorrect (false negative) by this test. Meaning, they were really positive.

So, here is the catch. Since you don't know before testing whether you are negative or positive, you don't know how accurate the result you are getting actually is.

You would be better off with the new "fourth generation" test that looks for both HIV antibodies and what is known as the p24 antigen. This HIV component is detectable far earlier, as early as a few days, after infection, before antibodies are detected. Approved by the FDA in August 2013, the Alere Determine HIV-1/2 Ag/Ab Combo test is available in doctors' offices and clinics.

This rapid version through a doctor's office is 96.6 percent accurate overall and is able to detect 54.4 percent of acute infections. Through a reference lab, the accuracy of this type of fourth generation test is 99.1 percent overall and is able to detect 87.3 percent of acute infections. So if you doctor sends this test to an outside lab, you are most likely to get the most accurate answer.

Knowing if you have a recent infection is important for treatment decisions as this is when you are most at risk of infecting others. Obviously, home testing will miss any other STD you might have picked up.

Q. I just read that gay and bisexual men were at a really high risk for syphilis. Do people still really get that? It just takes a shot of penicillin to get rid of it, right?

A. The answer is a resounding yes to the first part of your question. Over the past several years, increases in syphilis among MSM have been reported in major U.S. cities from Miami to New York and Seattle to San Francisco. In 2013, 75 percent of the reported cases were among MSM. High rates of HIV co-infection were found, ranging from 20-70 percent.

It is well known that the genital sores of syphilis make it easier to transmit or acquire HIV. The prevalence reported in 2011 by the CDC was 2.6 percent among HIV-negative MSM and 10.1 percent among HIV-positive MSM. And that is not the only higher risk STD among MSM. Similar trends were also found for gonorrhea and chlamydia infections as well.

Also of significant concern is the high-risk human papillomavirus (HPV) infection which is especially common in HIV-infected MSM and is associated with anogenital cancer. While a shot of penicillin can get rid of the earliest stage of syphilis, HPV is not so easily cured. This is another set of reasons for not solely relying on home HIV testing in place of your visit to your doctor.

Called "more than a doctor, a trusted friend" by his patients, Dr. Howard Scheiner is a true native New Yorker. He was born in the Bronx, he attended the esteemed Bronx High School of Science and City University of New York before receiving his medical education at The Mount Sinai School of Medicine. Truly a Renaissance man, in addition to his lifelong service to the medical profession, Dr. Scheiner is a published author, playwright and musical composer. Combining all his loves, he is perhaps most proud of founding "The Brent Varner Project, Inc." a charity that provides free HIV services to those in need through the Actors Fund of America.

This story is part of our special report: "Ask the Doc". Want to read more? Here's the full list.

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