Take a swab of saliva from inside your mouth. Put it into a vial of test fluid, and 20 minutes later you'll learn whether you're infected with the virus that causes AIDS (search).

The OraQuick Advance test is already widely available in health clinics and doctors' offices. The Food and Drug Administration is considering permitting it to be sold over the counter.

Supporters of home kits say they will spur more people to get tested and get treatment sooner if infected. However, concerns have been raised about whether a doctor or counselor sh health care worker, or the requirement of mailing a sample to a lab.

The maker, OraSure Technology (search) of Bethlehem, Pa., has not decided how much it will charge consumers for the kit, said Ron Spair, the company's chief financial officer. The company sells the kits for between $12 and $17 to clinics and doctors, he said.

The test is accurate more than 99 percent of the time, Spair said. Still, a positive result from the test should be confirmed through an additional test by doctors or public health officials, he said.

To take the test, a person swabs the inside of their mouth, between their cheek and gum, to insert their saliva into a vial of fluid that comes with the kit. Twenty minutes later, an indicator will light up if the test detects the presence of HIV-1 or HIV-2 antibodies.

Those antibodies become present in the body several weeks after a person acquires HIV; the test will not detect the virus if it was more recently acquired.

On Nov. 3, FDA's Blood Products Advisory Committee, will consider whether to recommend the product for over-the-counter sales. The FDA (search) has the final say; it usually follows the advice of its advisory committees.

FDA briefing documents posted on the Internet said these kits could lead to more people knowing whether they have HIV, which could mean earlier treatment of the infection. People afraid or unwilling to take the test, particularly those without any symptoms, may more readily test themselves with a kit they can use privately.

"Knowing your status is critically important," Spair said. "We want to provide that opportunity to the broadest number of people possible."

But the documents also note concerns about someone learning they probably have HIV when they are alone, with no health professional or counselor nearby.

The kits are a good idea, said Terje Anderson, executive director of the National Association of People with AIDS. He said he doubts they will be as popular as at-home pregnancy test kits, suggesting most people who want an HIV test would prefer to be with a doctor. Their use may also depend on their price.

"Overall, I would say they are a step forward," he said. "Anything that helps more people learn their status is a good thing."

But the discovery one has HIV (search) is "potentially traumatic," he said.

"There have got to be safeguards built in so they can get all the support they need," he said.

Spair said the company would work with FDA to develop instructions with the kit for someone who receives a positive result. He said he expects a telephone number and a web site address would be part of those instructions.

"We, together with the FDA, want to make sure that the infrastructure is in place so that folks on a 24-7 basis have access to counseling," he said.

Some companies market unapproved HIV tests for home use; the FDA says it is impossible to know if they are reliable.

One test, made by Home Access Health Corp., is approved for sale in the United States by the FDA. People taking this test must take a sample from themselves and mail it to a lab for testing.

About 1 million people in the United States are believed to have HIV. The Centers for Disease Control and Prevention estimates nearly 300,000 people have the virus but don't know it.