STD testing windows guide

What is a "testing window"?

A testing window is the period of time between exposure to an infection and detection of an infection through a blood or urine test.

STD tests are designed to detect signs of infection, which usually take time to develop after the initial sexual contact or other moment of transmission. For example, if you had sex with someone who has an STD and you became infected, you probably wouldn't test positive for the recently-acquired infection right away.

Every infection has a different testing window – also called an incubation period – ranging from a few days to several months after possible exposure. As a rule of thumb, our physicians recommend testing at three weeks after a possible recent exposure to an STD...but because not all infections will show up in that timeframe, we recommend testing again at three months after exposure.

There isn't one right answer...

...for when to get tested after possible exposure to an STD. Because there is great variability regarding when a person will show a definitive positive or negative test result, the medical team has developed the following chart based on the best data available.

To help you decide when to get tested, the "Most Likely Detection" column indicates the standard timeframe in which most people will show accurate test results. If you test earlier than this recommended time frame, there's a chance that the test will miss the infection; if you test later, it's more likely that the test will be definitive...but some people would rather get tested as soon as possible for peace of mind. From our perspective, the "Most Likely Detection" column provides the right balance between getting tested too early, or waiting longer than necessary.

*According to the CDC, most people infected with HIV will develop detectable antibodies within 25 days of exposure and 97% of people will have HIV antibodies by three months after exposure.

**The majority of people with syphilis will have a positive test result within six weeks.

What is "seroconversion"?

Related to testing windows, seroconversion is the point at which the immune system has developed the antibodies needed to fight infection ("sero" means blood, or serum). For example, what is the window period for HIV? The HIV Antibody test is most reliable after three months when serconversion to the virus has most commonly occurred. According to the Centers for Disease Control and Prevention (CDC), most people infected with HIV will develop detectable antibodies within 25 days of exposure and 97% of people will have HIV antibodies by three months after exposure.

What is a "false-positive" or "false-negative" test result?

As with most medical tests, there's a slight chance (1-4%) that a positive test result indicates an infection when there isn't one (false-positive); or a test comes back negative, despite the presence of infection (false-negative). For example, a false-negative test result can happen if an infected person tests too early for an infection to be detected...that means it's possible to get a negative test result but still have an STD.

If you're concerned about the reliability of your test results for any reason (e.g., timing, or your sexual history, or your partner's sexual history), we recommend that you get re-tested to confirm your results...and to minimize the risk of being a carrier of an STD and potentially developing more serious symptoms down the road.

_{Last reviewed by Medical Director Lisa Oldson, MD, January 2011.}