But the agency warned that the saliva test is not as accurate as the current tests that use blood, and recommended blood tests to confirm the presence of the virus.
The approval was one of two major actions by the agency Friday, the other being an announcement that saline breast implants will be allowed to remain on the market for at least another three years while safety studies are being conducted.
The approval of the saliva test is expected to be welcomed by much of the AIDS community because it provides an option that may encourage more individuals to be tested, particularly those who are reluctant or fearful of having blood drawn.
"Anything that makes it easier to get tested and speeds diagnosis is a good thing," said Dr. Mervyn F. Silverman, president of the American Foundation for AIDS Research.
The test, which will be sold under the brand name of OraSure, is manufactured by Epitope Inc., of Beaverton, Ore. Company officials said they expect the test to be available within six weeks.
It is believed to be the first such test approved by the FDA that uses oral specimens in disease detection. Like the blood test, it detects antibodies to the virus.
The company predicted the technology would be applied in the future to test for additional diseases, such as measles and hepatitis, and to aid in the monitoring or detection of certain therapeutic drugs and drug abuse.
"This is an important day in the fight against AIDS," said Adolph J. Ferro, president and chief executive officer of Epitope. "The availability of OraSure will broaden access to testing for HIV infection. . . . We are determined to bring the product to the broadest possible market as rapidly as we can."
The test must be administered by physicians, and is not available for home use, said the FDA, which is still deliberating whether to approve a home collection blood AIDS test kit.
However, Ferro said the company eventually hopes to apply for FDA approval to market the test over-the-counter for home use collection of specimens, should the concept of home collection be sanctioned by the agency.
In this scenario, the test results are not actually obtained in the home. An individual would collect a sample at home, whether blood or saliva, but it would still be sent to a laboratory for analysis. Advocates of home collection say it would help those who wish to avoid having to visit a physician or a clinic in person.
The OraSure device consists of an absorbent pad mounted on a lollipop-style plastic stick. The pad, which is treated with a proprietary salt solution to enhance collection of antibodies in the oral cavity, is placed between the lower cheek and gum for two minutes. The fluid specimen is then placed in a sealed vial that contains a preservative solution and sent to a lab for analysis.
"It is a non-invasive form of testing," Ferro said. "There is no danger of a needle-stick accident. It is relatively easy to obtain a specimen. The services of a trained phlebotomist are not required. As a result, we believe OraSure will be less costly to use."
The cost of the device will be about $2 to $4 a unit, excluding the laboratory analysis, Ferro said. He estimated that lab costs will add an additional $3 to $15 a test. The standard blood tests that detect HIV antibodies cost about $30.
The FDA cautioned that the saliva test may miss one or two infected individuals per 100 infected people tested, and may also result in false positives at the same rate in the uninfected. For this reason, the agency recommended that those who test positive by saliva undergo confirmatory blood tests to establish true infection.
The announcement that saline breast implants will remain on the market keeps an important option open for women seeking cosmetic augmentation or breast reconstruction. In 1992, after a bitter and emotional debate, the agency removed silicone gel breast implants from the general market after safety questions arose.
The silicone devices are available now only to women undergoing reconstruction, after mastectomy, for example, and to a small number of women for cosmetic purposes as part of ongoing clinical studies.
The saline devices, which are filled with saltwater, are believed to have a much lower degree of risk associated with their use. Like the silicone implants, they were on the market before 1976, when Congress gave the FDA regulatory authority over medical devices.
At that time, manufacturers were not required to meet current safety standards. However, the law provided that manufacturers of devices already on the market could later be required to prove they are safe.
Earlier, the FDA told the manufacturers of saline implants--McGhan Medical Inc. and Mentor Corp., both of Santa Barbara--that they would be required to conduct safety studies of their products, and submit the data for review.
The studies are slated to be completed by 1998. In the meantime, the FDA said it would monitor the ongoing studies "and will make public any significant new health information" they provide, if necessary.