The HIV 4th Generation Test is one of the most accurate and fastest way to determine is a person has been infected with HIV or not.
The HIV 4th Generation Test is also called the Combo test or the Duo test.
It tests for both the HIV antibodies as well as the antigens in the blood. It can be done as a rapid test i.e. you can get the results in 20 minutes.
Antibodies are produced by the body when it is infected with the HIV virus. There are many different types of antibodies. The one that is produced the earliest is called the IgM antibody. This can be produced as early as 20 days post exposure. 3rd and 4th Generation HIV tests can detect the IgM antibody.
Antigens are bits of the HIV virus shell that can be found in the blood as early as 14 days post exposure. The 4th Generation test can detect the presence of this antigen.
If the test detects either the presence of HIV antibodies or antigens, it means the patient is most likely infected with HIV. This has to be confirmed with another ELISA test. We always do at least 2 tests before diagnosing a person as HIV +ve.
Officially it is conclusive at 28 days post exposure. However, from current scientific data, we know that when the test is done at 20 days post exposure, it is already as good as 100% accurate. Personally I have tested patients +ve for HIV at only 14 days post exposure with this test.
The US CDC recommends the HIV 4th Generation test for all HIV screening. This is because it is more accurate, has a shorter window period and can pick up rare cases of sero-negative infections (see below).
The HIV 4th Generation test can detect HIV infections in very rare cases of people who are infected with HIV but never produce any anti-bodies. These are called sero-negative infections and happen in about 1 in 1 million people.
At our clinics the HIV 4th Generation test costs $150 (before GST).
You can walk in our clinics at Robertson Walk, Bencoolen Street, Novena Medical Center or Scotts Road anytime during our opening hours for this test. It only requires a finger-prick of blood and 20 minutes to get results.