HOW ACCURATE IS THE HIV TEST?
By Celia Farber
Mothering Sept./Oct. 1998
People often discuss the dreaded "AIDS test" as though it is AIDS
itself that is being tested for. It is not. What the "AIDS test"
actually detects is antibodies to HIV, which may or may not entail
true infection with HIV. (1) Traditionally, antibodies have signaled
that an infection has been defeated. In AIDS, however, for reasons
that remain unresolved, the antibody has come to be synonymous
with bad news -- a categorical signal that the person "has" HIV and
perhaps even "has" AIDS.
Rarely, if ever, has a single diagnostic test had such an enormous
impact on the lives of the millions of people who rely on it. Since
1985, the U.S. government and various civilian institutions have
performed more than 20 million HIV tests every year. Responses to
positive tests have been melodramatic. People have been known to
commit suicide or murder, lapse into depression, have abortions,
become divorced, and take toxic medications. (2) Tragically, these
dramatic actions were triggered by a test that is far from foolproof.
In 1993, a group of Australian researchers published what would be
the first substantial critique of the HIV antibody test. The article,
entitled "Is a Positive Western Blot Proof of HIV Infection?" was
published in the journal Bio/Technology, a respected scientific
publication affiliated with the British magazine Nature. The
Australian researchers stated that the HIV test is seriously flawed
on several counts: it is not standardized, so different labs will
interpret the same results differently; it is not reproducible (the
test fails when tested against itself); it cross-reacts with other,
non-HIV proteins; and it lacks a true "gold standard." Every
diagnostic test must have a gold standard, which in this case would
be HIV itself, but the authors argue this is impossible since the HIV
virus has never been isolated in pure form. (3)
The scientists scrutinized the two most widely used HIV antibody
tests -- the "ELISA," which is used to screen blood, and the "Western
Blot" (WB), which is used to confirm a positive result on the ELISA.
The problems apply to both tests.
The ELISA test, first developed in 1985, is highly sensitive and also
extremely nonspecific, which means it gives a positive result even
when there is no HIV present. As many as four out of five ELISA
tests cannot be confirmed by Western Blot, (4) and yet it remains
the most widely used test in the Third World, most notably Africa,
where HIV is said to be rampant.
Citing the data from a mass HIV testing program undertaken by the
U.S. military, the Australian researchers revealed some startling
findings. There were, for instance, 4,000 people who had two
positive ELISAs followed by a negative WB. Perhaps worse, there
were 80 cases of people who had two positive ELISAs, a positive WB,
followed by a negative follow-up WB.
In other words, those 80 people, outside the context of this study,
would have gone home believing they were HIV positive, since a
single positive WB qualifies a person as positive. But in fact they
Another problem with the test is that it is nonspecific. The test
looks for patterns of proteins thought to be specific to HIV. One
protein in particular, p24, is "currently believed to be synonymous
with HIV isolation and viremia," the study says. But the Australian
researchers detected p24 antibodies in a number of people who were
completely free of HIV, including one out of every 150 healthy
people, about 13 percent of all people with generalized warts, and
more than 40 percent of those with multiple sclerosis. On the other
hand, they point out, p24 is not found in all AIDS patients.
But perhaps most troubling, the tests tend to cross-react with other
microbes. The Bio/Technology articles describes a tribe of
Amazonian Indians who have never had contact outside their tribe
and who have no AIDS. And yet, 3.3 to 13.3 percent were HIV-
positive by Western Blot. "The above data," they speculated in their
final report, means either that HIV is not in fact causing AIDS, "or,
that the HIV antibody tests are non-specific."
The test's greatest failing in the eyes of those who've had to rely on
it, however, is that it is not standardized. In the Australian study,
one particular blood sample was sent 89 times to three different
labs. It was reported to be positive 64 times, indeterminate 23
times, and negative once. There is such a broad, gray,
"indeterminate" zone, in fact, that it's often merely chance whether
a given lab reads the result as positive or negative.
Christine Maggiore, president of the dissident AIDS-activist group
HEAL in Los Angeles, experienced this first-hand. After initially
testing HIV-positive, and going into the emotional tailspin that such
a result often sets off, she subsequently repeated the test four more
times, and got every possible result on the spectrum -- positive,
negative and indeterminate. "This is why I tell people not to take the
test," she says emphatically. "It's just too unreliable. It shouldn't be
how we measure our health." *
Celia Farber has written on the issues and controversies surrounding
HIV, AZT, and AIDS for more than a decade. She is a regular
contributor to Esquire, Spin, USA Today, and Gear, among other
national publications. She is the mother of one son and resides with
her family in New York City.
1. P. Duesberg, Inventing the AIDS Virus (Washington, D.C.: Regnery
Publishing, 1996), 207-209.
2. J. Shenton, Positively False, 53-73.
3. E. P. Papadopoulous-Eleopulos and V. Turner, "Is a Positive
Western Blot Proof of HIV Infection?" Bio/Technology (2 June 1993):
4. R. Root-Bernstein, Rethinking AIDS (New York: Free Press), 51.