The United States announced Tuesday it has authorized sales of the first over-the-counter home testing kit for HIV, the virus that leads to Acquired Immune Deficiency Syndrome (AIDS).

The OraQuick In-Home HIV test is expected to be available from October at 30,000 American retail outlets, its manufacturer said, with the kit allowing people to obtain a result within 20 to 40 minutes.

The US Food and Drug Administration (FDA) and the company that makes the kit, OraSure Technologies, hailed the approval as a major advance in detecting Human Immunodeficiency Virus infections.

The test procedure involves taking an oral fluid sample collected by swabbing the upper and lower gums inside a person's mouth, placing the sample into the kit's developer vial and then waiting for the result.

The FDA noted that a positive result from the test does not mean a person is definitely infected with HIV, but rather that an additional test should be done in a medical setting to confirm the result.

"Similarly, a negative test result does not mean that an individual is definitely not infected with HIV, particularly when exposure may have been within the previous three months," the FDA said in a statement.

The home testing kit, which detects both type 1 and type 2 HIV antibodies, could identify large numbers of previously undiagnosed infections, according to the FDA.

Clinical studies for self-testing have shown that the OraQuick home HIV test has an expected performance of 92 percent for test sensitivity, the percentage of results that will be positive when HIV is present.

"This means that one false negative result would be expected out of every 12 test results in HIV-infected individuals," the FDA said.

Similar testing indicates that one false positive would be expected out of every 5,000 test results in uninfected individuals, according to the FDA, which is responsible for regulating medication in the United States.

A spokeswoman for OraSure Technologies said a price for the over-the-counter test kit had not been decided but it would likely be higher than the $17 charged for a similar unit that the company already sells to hospitals, clinics and physicians.

The company's president and chief executive Douglas Michels said the test would allow people "to learn their HIV status in the comfort of their home and obtain referral to care if needed."

The Centers for Disease Control and Prevention estimates that 1.2 million people in the United States are living with HIV infections -- of which about one in five are not aware they are infected.

There are about 50,000 new HIV infections every year and many of those infections are transmitted from people who are unaware of their HIV status.

"The availability of a home-use HIV test kit provides another option for individuals to get tested so that they can seek medical care, if appropriate," said Dr Karen Midthun, director of the FDA's Center for Biologics Evaluation and Research.

"Knowing your status is an important factor in the effort to prevent the spread of HIV."