July 19, 2013
Table of Contents
What Is HIV Testing?
HIV testing tells you if you are infected with the Human Immunodeficiency Virus (HIV) which causes AIDS. Most of these tests look for "antibodies" to HIV. Antibodies are proteins produced by the immune system to fight a specific germ. Newer HIV tests look for signs that the virus itself is in the blood.
People who already know they are infected with HIV might get other "HIV" tests. These measure how quickly the virus is multiplying (a viral load test, see Fact Sheet 125) or the strength of your immune system (a CD4 count, see Fact Sheet 124).
How Do I Get Tested?
You can arrange for HIV testing at any Public Health office, or at your doctor's office. Test results are usually available within two weeks. In the US, call the National AIDS Hotline, (800) 342-2437.
The most common HIV test is a blood test. Newer tests can detect HIV antibodies in mouth fluid (not the same as saliva), a scraping from inside the cheek, or urine. "Rapid" HIV test results are available within 10 to 30 minutes after a sample is taken. In November 2010 the FDA approved the INSTI test, which gives results within 60 seconds. In 2012, the FDA approved the first true "in-home" HIV test. It uses a mouth swab and shows results in 20 to 40 minutes. A positive result on any HIV test should be confirmed with a second test at a health care facility.
Many people are infected with HIV but don't know it. You might not feel sick or have any health problems. But you can still pass HIV to other people. Anyone who is sexually active should get tested regularly for HIV. In 2013, a US panel of experts recommended that everyone between the ages of 15 and 65 be tested, even if they have no known risks of HIV infection. This should make it easier for the cost of the test to be reimbursed by insurance companies.
If you are infected with HIV, it usually takes from three weeks to two months for your immune system to produce HIV antibodies. During this "window period you can test "negative" for HIV even if you are infected. If you think you were exposed to HIV, you should wait for two months before being tested. You can also test right away and then again after two or three months. If you are infected, you can transmit HIV to others during the window period even if you test negative. In fact, during this period of early infection, you have the greatest chance of passing HIV infection to others.
About 5% of people take longer than two months to produce antibodies. Testing at 3 and 6 months after possible exposure will detect almost all HIV infections. However, there are no guarantees as to when an individual will produce enough antibodies to be detected by an HIV test. If you have any unexplained symptoms, talk with your health care provider and consider re-testing for HIV.
Viral load tests detect pieces of HIV genetic material. They show up before the immune system manufactures antibodies.
In 2010 the FDA approved a new blood test that detects both antibodies to HIV and HIV antigens (pieces of the virus.) This "fourth generation" test produces results faster than an antibody test.
What Does It Mean if I Test Positive?
A positive test result means that you have HIV antibodies, and are infected with HIV. This can be a very difficult time. Be sure to get information and help. See Fact Sheet 201, "How Do I Start?"
Testing positive does not mean that you have AIDS (See Fact Sheet 101, What is AIDS?). Many people who test positive stay healthy for several years, even if they don't start taking medication right away.
If you test negative six months after you think you were exposed to HIV and if there is no chance you were exposed to HIV since then, you are not infected with HIV. Continue to protect yourself from HIV infection (See Fact Sheet 150, Stopping the Spread of HIV).
This article was provided by AIDS InfoNet. Visit AIDS InfoNet's website to find out more about their activities and publications.