Washington ? People will soon be able to learn before leaving the doctor’s office if they’re infected with the AIDS virus.

The government on Thursday approved a 20-minute HIV test that AIDS experts say is so easy to use it will greatly cut the number of people who unknowingly carry and spread the disease.

It’s not the first rapid HIV test. A competing version has been sold since the mid-1990s, but it is so difficult to use that few clinics offer it. Today’s routine HIV tests take up to two weeks to provide results, and at least 8,000 people a year who test positive at public clinics never return to get the news.

The new OraQuick test should slash that number and encourage more of the almost quarter-million Americans who don’t know they’re infected to seek testing, federal scientists said Thursday in announcing Food and Drug Administration approval of OraQuick.

This is “a very, very important milestone,” said FDA science chief Dr. Murray Lumpkin.

To use OraQuick, a health worker pricks a person’s finger, drops a spot of blood into a vial of developing solution and drops in the sticklike testing device.

The dipstick gives results similar to common pregnancy tests: One reddish line means no HIV. Two reddish lines mean the person may be infected and needs a confirmatory test to be sure.

OraQuick at first will be available only in hospitals and large health clinics because of a law that restricts who can use certain types of medical tests.

But the test is so simple that Health and Human Services Secretary Tommy Thompson urged manufacturer OraSure Technologies Inc. to seek a waiver of that law allowing OraQuick to be sold in more places ” from small doctors’ offices to mobile testing vans and even HIV counseling centers staffed by social workers instead of health professionals.

The company will begin selling OraQuick around year’s end.