|
FDA approves two new tests for HIV infection
Oral exam - the process is as reliable as blood tests, authorities say.
Americans got two new tests for the AIDS virus on June 3rd: one to more
easily detect infection and the other to prevent how fast patients with
the deadly disease will sicken.
The
Food and Drug Administration called Epitope Inc's Orasure the first oral
test that appears as reliable as the standard blood test to diagnose the
HIV virus that causes AIDS.
Orasure
uses a treated cotton pad to scrape a tissue sample from between the gum
and cheek. The sample is tested for antibodies to HIV. Doctors predict wide
use by people at risk for HIV but who shunned blood tests.
Patients
who already know they're infected can find out just how much HIV is floating
in their blood with Hoffman - La Roche's Amplicor test approved on June
3rd.
But
the question is whether patients will want this test, said Dr. Curtis Scibner,
FDA's deputy director of blood research.
Studies
do show that patients with high HIV blood levels are more likely to sicken
fast - but nobody knows if drugs that lower those blood levels significantly
reduce the risk of death or even if changes in HIV amounts signal it's time
to change treatments.
Cutting edge of science
"We are at the cutting edge of science and medicine right here,"
Scribner said. "We have not answered all of the possible questions,
but other valuable information is becoming available everyday."
Still,
Roche will offer baseline Amplicor testing for free to any HIV - infected
patient for 60 days starting June 17th. If the test is completed at a later
date, the cost will be approximately $150 to $200.
Doctors
now gauge AIDS progression by measuring levels of an immune cell called
CD4 that is a main target of HIV, However, it is not unusual for some people
to have no AIDS symptoms despite very low CD4 levels.
Meanwhile,
the first generation of Orasure was approved in 1994. However, it used a
less sensitive method to screen for HIV antibodies, called the ISA test.
In
the past people who tested positive then had to undergo a more sensitive
blood test, called the Western blot, to be certain the deadly virus was
present. On June 3rd, the Food and Drug Administration approved the new
version of Orasure that allows Western Blot testing of the oral sample instead
of blood.
99.9% as accurate
Clinical trials showed the Orasure Western Blot test was 99.9 percent
as accurate as the traditional blood test.
"It's
exactly the same," said FDA's Scribner. " Many people don't like
to get stuck for a blood sample, so in this case they could use an oral
fluid sample."
The
FDA approved the original less sensitive Orasure because doctors needed
a way to reach people at risk of HIV but who shunned blood tests, Scribner
explained. The theory was that a positive oral test would persuade such
patients to accept a little blood - letting for confirmation that they were
infected. "Now that confirmation can occur right on the oral fluids,"
he said.
An
oral test is good for health workers, too, because they won't ruin the risk
of sticking themselves with the needle they just used on a possibly infected
patient, explained Donna Sturgess of SmithKline Bleecham.
It
will cost about the same as a blood test, which averages about $50 - $60,
and doctors will receive the results within three days, she said.
Orasure
is supposed to be used only by health care providers, but SmithKline and
Epitroval for a home test.
Source: Pacific Daily News from Washington DC (AP) 6/3/96 |