How Long Should I Wait for STD Testing?

Chlamydia screening smear test

Probably about half of the e-mails I receive are asking the same question. "How long do I need to wait before I go for STD testing?" 

In general they're from people who had unsafe sex and wondering how soon they can reliably find out if they acquired an STD. However, there are variations.Some people cheat on their partners and want to know if they need to say anything. Others are regretting an encounter with a sex worker.

Still, the basic question remains the same:

If I have been exposed to an STD, how long do I have to wait before I know any infection will be detected by an STD test?

How Soon Will an STD Test Be Accurate?

Unfortunately, the question of when to get an STD test is not easy to answer. To start with, STD testing isn't perfect. Even if you have theoretically waited long enough for a test to work, you could still end up with a false positive or a false negative. You also need to account for the fact that not all STD tests work in the same way. Some tests look directly for the presence of a pathogen. Others look for your body's immune response to the infection.

In theory, tests that look directly for the pathogen should become positive faster. That's because pathogens are there from the start of the infection. However, these tests often require samples from an infected location to work.That's not always easy to come by.

For example, herpes swabs are notoriously sensitive to timing. They only work during a very short window of active infection. Still, the accuracy and ease of these tests is very disease dependent. New tools have allowed doctors to develop reliable urine testing for chlamydia and gonorrhea. Other infections, such as HPV and herpes, may be more difficult to detect without the presence of an obvious sore or lesion.

In contrast, blood tests that look for antibodies don't require a doctor to know where to sample. What they do require is time to turn positive. Your body's immune system must first react to the infection and then produce detectable levels of antibodies for these tests to work. Different types of antibodies peak at different times after infection. In some cases, this fact can be used to determine how long you've been infected with an STD. However, the delayed response also affects how long it takes for a test to become reasonably predictive of infection.

So How Long Should I Wait To Get Tested? 

Answering how long it would take for someone to definitively test positive or negative on an STD test after a risky sexual encounter requires knowing a number of things. These include:

  • what STDs the person had been exposed to
  • what tests were being used to detect the infection

There are also a number of other, more nebulous factors that could play a role. Unfortunately, this makes it impossible to give someone a definitive answer on how long they should wait to go get a test.

It's a difficult question even from a research standpoint. How do you ethically and practically expose someone to an STD and then repeatedly test them to determine how long it takes for them to test positive? Because of this, there is little to no solid data about how long after an exposure people should wait to get tested for many STDs.

Common practice suggests that people could go in for basic testing for bacterial STDs as soon as 2 to 3 weeks after an exposure. (They could, and should, go even sooner if they have symptoms.) However,they would need to be retested again at least three to six months out in order to feel relatively certain of their results.

At a month out, some tests for chlamydia and gonorrhea would be reasonably accurate. Still, tests for other diseases such as herpes and HIV take longer to become conclusive.

If you had a particularly high-risk encounter, 6 months is a pretty conclusive follow-up period for most STDs. That doesn't mean you don't want to get tested sooner. It just says when you might want to go back to a standard screening schedule

How Long Do STD Test Results Take?

Once you've gotten tested, you have to wait for results. There are some rapid STD tests available. These can give results in an hour or less. However, not every clinic stocks rapid tests. They're also not available for every STD. If you're interested in rapid tests, your best bet is an STD clinic. You can call in advance to ask what rapid testing is available.

Without rapid testing, STD test results may come back anywhere between 48 hours and two weeks. That's why you don't want to just ask how soon your STD test results will come back. It's also a good idea to ask your doctor whether they'll call with any results or only positive results. Otherwise, you may be waiting  for an all clear that will never come. 

STD Testing Isn't Everything

There is another question that people are often asking - explicitly or not - in testing e-mails. That question is, "do I have to tell current/future partners that I might have been exposed to an STD?" Whether the question is modified by  "what if we only had oral sex?" or "what if it didn't last long?" my answer is usually the same.

These are discussions that everybody should be having before they have sex.

Most people don't come to sexual relationships completely inexperienced. Therefore, talks about testing and safe sex are not just appropriate but smart. Still, sometimes people can't bring themselves to have the discussion. That's why it is always a good idea to practice safe sex. That's particularly true until you are reasonably certain of your test results. Condoms may not be perfect. They are still far better than doing nothing at all.

The question of disclosure is certainly more complicated for people who have been unfaithful to a current partner. However, I have to believe that more people would be willing to forgive an infidelity that didn't unknowingly expose them to STDs than one that did. When someone discloses an infidelity, they at least give their partner a chance to minimize their emotional and physical risk.

People have certainly used STD transmission as a tool of manipulation. However, infecting someone with an STD is not a healthy way to make a partner stay with you or to convince them to overlook an infidelity. Fortunately, once most people get over the initial shock and the stigma of an STD diagnosis, they realize that fear isn't love. Dating with STDs may not always be easy. However, it's better than staying with a partner who is emotionally or physically abusive.... For the record, most people would consider intentionally infecting a partner with an STD to keep them around as a form of abuse. 

Kettle H, Cay S, Brown A, Glasier A. Screening for Chlamydia trachomatis infection is indicated for women under 30 using emergency contraception. Contraception. 2002 Oct;66(4):251-3.

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