One of the most commonly asked questions about getting tested for HIV is:
"If I did get infected with HIV, when will it show up on an AIDS Antibody Test?"
The HIV antibody test does not detect HIV directly but looks for antibodies to HIV. Antibodies are factors that are produced by the body to fight infections. Antibodies take time to form. The test will not be positive until enough antibodies are present in the blood for the test to find them. Different people take different amounts of time to develop antibodies after being infected. Some people will develop antibodies very quickly while others will take a longer time.
This time period between when a person is actually infected with HIV and when antibodies to HIV can be detected in the test is called the window period.
Currently used antibody tests are more sensitive than those used in the past. Most people will develop detectable antibodies by 30 days after infection with HIV 1,2. Nearly everyone who is infected with HIV (99%) will have antibodies detected by 3 months after infection 3. Rarely do people take longer than 3 months, but it can happen 4.
A person may need to wait at least 6 weeks from the time they thought they could have gotten the virus before taking the test. Waiting longer, up to three months, will give better information about whether they are actually infected with HIV.
Sometimes people are not sure whether they should get a test or wait. Some people might need to get tested again if they take the test too soon. People who have a higher chance of being infected are encouraged to have the test every three months. Those with a higher chance of being infected include:
- People having sexual contact with someone who is HIV positive
- People having anal sex (butt sex) without a condom and having frequent anonymous partners
- People who share needles or other drug injection equipment
Because newly infected people are most infectious to others, those waiting for a test during the window period can help prevent passing the virus to others by not having sex during this period or by using condoms during all sexual contacts (oral, anal or vaginal). They should also not donate blood or tissues during this period and make sure any drug injection equipment is used only one time and then thrown away safely.
Public Health - Seattle & King County has anonymous HIV testing available on a sliding fee scale. For more information about testing, safer sex, sexually transmitted diseases and safe disposal of syringes and sharps, please call the HIV/STD Information Hotline at 206-205-7837.
HIV/STD Information Line
206-205-7837
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References:
| 1 |
Busch MP, Kleinman SH and Nemo GJ. Current and Emerging Infectious Risks of Blood Transfusions. Journal American Medical Association, Feb 26, 2003; 289(8): 959. |
| 2. |
Lindback S, Thorstensson R Karlsson AC et al. Diagnosis of Primary HIV-1 Infection and Duration of Follow-up after HIV Exposure. AIDS, 2000; 14(15): 2333-2339.
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| 3. |
Lindback et al.
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| 4 |
Ciesielski CA and Metler RP. Duration of Time Between Exposure and Seroconversion in Healthcare Workers With Occupationally Acquired Infection with HIV. American Journal of Medicine, May 19, 1997; 102(5) Supplement B.
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