How safe are you?

HIV/AIDS testing turns up false-positive — and false negatives
Second in a three-part AIDS series

By Victoria A. Brownworth
PGN Contributor
© 2008 Victoria A. Brownworth and Philadelphia Gay News

Jane Greeley* had been trying to get pregnant for a year when the stick finally turned blue. But when she left the gynecologist’s office, it wasn’t in the ecstatic state she’d expected. Greeley was indeed pregnant. She also had AIDS.

“I was gob-smacked,” Greeley said in a telephone interview. “I mean, the floor just dropped out from under me. How was this even possible?”

The same broad-spectrum blood test that confirmed Greeley’s pregnancy also confirmed her HIV-positive status — and that her T-cell count was hovering at 300, which meant she had full-blown AIDS.

Greeley, who identifies as bisexual but whose primary relationships are with men, had prepared for her pregnancy on every level, which included regular HIV testing.

“I got checked for everything once I decided I wanted a baby,” she explained. “HPV, chlamydia, gonorrhea, herpes and, of course, HIV. I was negative for everything.”

Only she wasn’t.

It had taken Greeley more than two years to conceive. During that period she was monogamous with her now-husband, Dave, who is HIV-negative.

“I just couldn’t understand it,” Greeley said, her voice catching. “I did everything right. I was a safe-sex fanatic. I wasn’t wildly promiscuous, ever. And I had always insisted on getting everybody tested. My friends called me Miss OraSure [OraSure is an oral-swab test for HIV]. I was tested at least 10 times in the past 10 years and every test was negative. But one of them had to be wrong, because I have AIDS.”

Each of Greeley’s tests used the oral swab, until the blood test in her gynecologist’s office.

Once she discovered her status, Greeley had to decide what to do.

“I wanted a baby — we had tried for a baby for two long years. And,” the 40-year-old Greeley noted, “my clock was nearly ticked out.”

She opted to begin medication and have the baby. Her daughter was born HIV-negative.

Like Greeley, Todd Stone* had gotten tested regularly and practiced safe sex. But the day before Thanksgiving last year, Stone’s doctor gave him the bad news: He had full-blown AIDS. With a T-cell count of 175 and a viral load of 82,000, Stone was sick — very sick. So sick, in fact, that had he not gotten tested when he did and begun treatment immediately, he might have died.

“It’s a piece of news you never want to hear, but you have to be ready for it if you are sexually active,” Stone said with surprising equanimity. “But the more I thought about it, the more I wanted to know: How did this happen?”

Stone wasn’t talking about how he got infected. He was talking about why all his HIV tests had come back negative.

“Everyone hears about false-positives,” Stone said. “You hear about that all the time. But false-negatives? I hadn’t heard of any. I thought I had to be the only one.”

Dr. Mark Watkins, who has a large practice at 12th and Locust streets in the heart of the Gayborhood, says Stone and Greeley are not the only ones.

“I’ve had about 10 patients who’ve had this experience recently,” he explained. “It’s very hard to tell someone they have AIDS when they think they don’t. ‘But I was tested!’ they tell you. And then you have to say, ‘But you have thrush, so you can’t be negative.’ It’s very hard.”

Watkins, who treats many gay and bisexual men, is concerned that the rapid tests like OraSure or the corresponding finger-prick stick tests are not as accurate as they should or could be and that provider error can also be a problem.

The literature accompanying OraSure (the most widely used oral-swab test) refers repeatedly to the test as “highly accurate.” But according to the company, the test is actually between 90-95-percent accurate. As a source at OraSure Technologies Inc., who asked not to be quoted by name, explained, “There are a lot of variables. A lot depends on the person giving the test and how well trained they are. Most tests are 100-percent accurate if they are done correctly and stored correctly. But that’s just not always the case. And you can’t blame a test for human error.”

The Food and Drug Administration could not comment on how the accuracy data on OraSure were achieved. And the literature itself is clear: The swabbing must be done perfectly — thorough swabbing of the inner cheek and gum, then the swab must sit in the mouth in that spot for three full minutes.

The test results take 20 minutes.

According to the FDA, clinical studies conducted by OraSure concluded that “OraQuick correctly identified 99.6 percent of people who were infected with HIV-1 (sensitivity) and 100 percent of people who were not infected with HIV-1 (specificity).”

Further, the FDA’s Web site states that a statistical analysis of data would indicate that a “very small number” of people would have a false-positive, even though none were found in the original clinical trial. But, “a small number of people who are infected with HIV-1 will have negative test results.”

The FDA also states that the limitations of OraQuick are similar to limitations of other antibody tests.

As the clinical trial suggests, studies published in the New England Journal of Medicine and the Journal of the American Medical Association have shown that in current HIV-testing methods in the United States, false-negatives are actually more common than false-positives in the general population.

Watkins said many factors can be involved in either a false reading — positive or negative, both of which can be devastating to the recipient. Watkins believes there are many more chances for false readings with the rapid testing than with a full-spectrum blood test, which is what he does in his office.

“I do the blood test and a viral load and other testing,” he explained, noting he had discovered patients who were either HIV-positive or had AIDS when they had previously tested negative with the rapid tests.

“It is rather frustrating,” he said. “I will offer testing and people will tell me they are negative and I have to say, ‘But you have thrush. Well, obviously that test was wrong.’ And that is very hard for the patient to hear — and for me to say.”

Mazzoni Center, a local LGBT healthcare provider, conducts a large percent of HIV/AIDS testing and counseling in Center City. Stone and Greeley both said they were tested at Mazzoni and believed they had false-negative readings more than once.

Mazzoni Center (formerly PCHA) has been performing HIV/AIDS testing for more than 20 years. Like most HIV/AIDS counseling centers, Mazzoni primarily uses the rapid tests, particularly for off-site testing. The center used to use the OraSure swab test and, according to medical director Dr. Robert Winn, had some issues with false-positive testing.

However, Winn said he was unaware of any false-negatives.

“But I was tested there repeatedly, for years, and I am the false-negative,” Stone asserted.

Because Stone and Greeley were both tested anonymously, it is impossible to verify their earlier tests.

Winn voiced his concern that people may stop getting tested altogether if they believe the testing to be inaccurate. He explained in detail how false-negative readings could happen and the onus for those readings ultimately falls on the patient.

“There are two main scenarios that can lead to false-negative readings,” Winn explained. “There are two kinds of antibody tests — HIV-1 and HIV-2. The rapid tests just test for one of these strains, so the simplest form of false-negative would be obtained if the person tested has the other strain. But since HIV-2 is predominately found in Africa, the HIV-1 is what most people would be looking for in the U.S.”

Winn noted that Mazzoni discontinued the oral-swab testing because of the problem of false- positives and now uses the finger-prick test for rapid testing.

The finger-prick test, OraQuick, is made by the same company that makes OraSure and is, according to Winn, “the same device, but instead of rubbing it into your mouth, we prick your finger and draw blood. It’s the same technology.”

Mazzoni conducts rapid testing, which is what the center uses exclusively when doing testing in the field, but Winn said Mazzoni also does the full blood test, which takes days for results.

“We offer both to people who come to the center,” Winn said, “but people want results quickly and almost everyone asks for the rapid testing, even in the office.”

The second scenario Winn said can produce false-negatives is apparent as he delineates the complicated nature of exposure windows, which can be as short as 30 days and as long as six months.

“Someone who has an exposure [to unsafe sex] very well might test negative, but are actually positive in that window period,” Winn noted.

The reason for this is that while the body has already taken in the HIV virus, it has yet to produce enough antibodies to show up in either the blood or the saliva.

It’s the same concept as a pregnancy test. A woman might have conceived the night before, but it will take a full two weeks from conception for enough hormone to show up to be detected in either a urine or blood test.

“That’s the most common scenario and would be a true false-negative,” said Winn, adding, “It is a pretty sensitive test, so the windows close pretty quickly.” He said that anyone who has not had an exposure within six months, for example, and then is tested, can be certain that the results would be correct.

Greeley said she had no real symptoms of anything wrong when she went to the gynecologist. She had been feeling exhausted and had been nauseated, but had presumed that was related to the pregnancy itself and thought she was anemic. She also had a severe yeast infection, but she thought that too was pregnancy-related and treated it with over-the-counter medication. Only later did she discover it was actually thrush.

For Stone, getting sick was what led him to the doctor and to getting full testing.

Winn and Watkins both insist that many people ignore signs of sero-conversion, perhaps due in part to having been tested and found negative. During the sero-conversion process, each explained, people do get sick.

Winn said, “You can develop a really bad illness, like oral thrush. The CD4 count would be very low. People shrug it off and think ‘I got the flu’ when it is actually them sero-converting.”

James Kilroy* had just that experience when he was traveling across the country working on a book. Kilroy had been getting tested at different sites along the way.

“I think I had a total of nine tests in a year and a half. I was negative all along — from Boston to New York to Los Angeles,” he said. “When I got to San Francisco, I thought I had the worst bout of bronchitis ever, went to the ER and found I had AIDS. I was so freaked I had my sister fly out from Boston and get me.”

Like Greeley and Stone, Kilroy was a safe-sex fanatic, and while he acknowledges, like Stone, that he was having regular sex, he says he was never without a condom.

“I just couldn’t figure it out,” he insisted. “I just couldn’t imagine how I could be positive.”

Kilroy and Stone have a gay-male myth in common as well: They are both tops and both thought there was far less likelihood of them getting infected when they weren’t, in the words of Stone, “the recipient. I wasn’t the one taking in the bodily fluids. So I just thought my risk level was so much lower. And lower still because I always used a condom and would not have sex with anyone who wouldn’t.”

Watkins acknowledges that he is seeing an increase in new HIV cases because people think AIDS is over and that there’s a “cure,” and so prevention is now less of a concern.

“I am seeing cases among young gay men and older gay men — just like the studies are showing,” he said, a touch of sadness in his voice. “I see the safe-sex stuff being passed out at the bars — condoms and lube. Guys take the lube and leave the condoms. I tell my patients that if someone is saying to them that they can have sex with him without a condom, he’s saying that to everyone he has sex with. It’s not safe. And the best way to protect yourself is not just to be tested regularly, but to practice safe sex. I hear a lot of excuses about why patients didn’t practice safe sex, but no good ones.”

Winn believes that gay men need to consider their own behavior rather than depending on testing to keep them safe.

“Testing is accurate, but only in the context of your own experience,” he said. “If you are having lots of unprotected sex, then the windows of opportunity — and of appearing to be negative on a test — are going to overlap. For those men, I recommend frequent testing, every two or three months.”

Winn offers some guidelines for testing. “Don’t get tested the day after risky behavior. That will likely give you that false-negative and then you will think you are negative when you might actually be positive.”

Conversely, Winn notes, if you “get tested 100 times in a year, the law of averages would give you a false-positive when you really weren’t.”

There’s an underlying anger in Stone as he talks about his experience and the false-negative readings he got over eight years.

“I thought I was doing everything right,” he says. “I was doing everything right. I was practicing safe sex, I was getting tested, I was getting tested with partners. I was — I thought — protecting myself and everyone I had sex with.”

Winn puts it succinctly: “While I want to rejoice with people when they find out they are negative, I also want to say to them, ‘but you still could be positive.’ Because it’s not really about the test, it’s about the timing. People really need to keep that in mind.”

Watkins thinks the new CDC recommendations for opt-out testing are best. “A lot of gay men are still not out to their physicians — about 40 percent,” he cited. “Opt-out testing means the patient has to tell you that he doesn’t want to be tested for HIV. You don’t have to ask a patient if he wants to be tested and he doesn’t have to ask you — it’s part of a full blood work-up. I think that will help catch a lot more cases of HIV in the coming years.”

Stone is more definitive. He wants everyone to ask for the full blood test, not just the finger-prick or oral-swab test — the tests he believes failed him and allowed him to go from HIV-positive to full-blown AIDS without ever knowing he had the disease, despite having had between 10 and 20 tests that all came back negative.

“I’ve been getting tested back since it took 10 business days if you had the full blood test,” Stone said. “It was the worst 10 days of your life, that wait. But if that’s what it takes, then that’s what we need to do. Because this just isn’t the way anyone should end up. This isn’t the way we will stop AIDS from spreading.”

Next week: The high cost of living with AIDS.