Sexually transmitted diseases (STDs), or sexually transmitted infections (STIs), usually pass from person to person through sexual contact. Testing can help make sex safer and ensure people receive proper treatment for STIs
Each STI has its own incubation period, which is how long it takes for symptoms to appear. In some cases, it can take months for an STI to show up on tests. In other cases, it may only take days.
This article explores the incubation periods of different STIs, how soon people can get tested, and the importance of testing.
The incubation period is how long it takes for symptoms to appear after exposure. The window period is how long it takes to get a positive test result for the infection after exposure. These periods are often similar.
Some general symptoms that indicate a person might have an STI include:
- genital itching or burning
- pain during intercourse or urination
- a new or unusual discharge
- bumps or growths on or around the genitals
- a foul smell coming from the genitals or after sex
However, some STIs do not cause symptoms for many years, even though a person can still get a positive test result. This is why it is important to rely on testing, not just symptoms.
People at high risk of certain STIs should ask for a retest, even after a negative result. For example, the Centers for Disease Control and Prevention (CDC) recommend annual HIV testing for people at risk, such as those whose partners have HIV or people who share needles.
The testing window for common STIs is as follows:
|Type of STI||Pathogen type||Testing window||Type of test||When to retest after treatment|
|HIV||virus||10–33 days for a nucleic acid test. |
18–45 days for an antigen/antibody test.
23–90 days for an antibody test
|Blood or saliva test. Blood nucleic acid test gives earliest results||None|
|Chlamydia||bacteria||1–2 weeks||Blood or urine sample, or swab of the throat, rectum, cervix, or vagina||3 months|
|Trichomonas||protozoa (parasite)||1 week to 1 month||Swab of rectum, penis, or vagina||2 weeks|
|Syphilis||bacteria||Within 3 weeks after sores appear. Sores appear usually 1 week after exposure||Blood test||6 and 12 months|
|Gonorrhea||bacteria||5 days to 2 weeks||Blood or urine test. Swab of the anus, urethra, cervix, or throat||Test 2 weeks after treatment, or 2 weeks later after exposure if the first test is negative|
|Herpes||virus||1–4 months||Blood test or swab of a sore||None|
|HPV||virus||3 weeks to a few months||Pap smear in females only — no approved test for males||None|
|Hepatitis||virus||3–6 weeks for hepatitis B. 2–6 weeks for hepatitis C||Blood test||Retest 6 months later|
A nucleic acid test analyzes a blood sample for HIV. It can indicate a positive result 10–33 days after exposure. The antigen/antibody test, also a blood test, looks for HIV antibodies. It also looks for an antigen that the body produces before antibodies appear. It can get results 18–45 days after exposure.
The antibody test uses a blood or saliva sample to look for HIV antibodies. It takes the longest to get a reliable result, at 23–90 days after exposure. A person can be confident they do not have HIV if they get a negative test during the window period and have no subsequent contact with someone who could have the virus.
A doctor can test for chlamydia by swabbing the vagina, cervix, rectum, or throat, or by taking a urine sample. If symptoms appear, they usually present within 7–21 days of exposure. A test can normally detect chlamydia within 1–2 weeks of exposure.
A doctor can test for gonorrhea with a urine sample. In some cases, they may also swab the urethra, anus, throat, or cervix to get a more reliable result.
Most tests can detect the infection within 5 days to 2 weeks of exposure. If a test is negative shortly after exposure, a doctor may recommend retesting 2 weeks later, particularly if a person has symptoms.
Gonorrhea symptoms usually appear from 1 day to 2 weeks after exposure.
Herpes symptoms usually appear quickly. On average, they present 4 days after exposure, and the typical range is 2–12 days. In some cases, however, symptoms can be so mild that a person does not notice them.
A blood test can confirm a herpes diagnosis. The test may be positive within a month, and by 4 months, blood testing finds most cases.
While it is possible for males to pass human papillomavirus (HPV) on to a partner, the CDC have not approved a male test. Instead, doctors may test for symptoms of the relatively rare cancers that HPV can cause, including penile cancer.
In females, HPV rarely causes symptoms. If there are indications, they could appear months or years later. The most reliable test is a Pap smear, which involves swabbing the cervix. This can detect HPV 3 weeks to a few months after exposure.
In some cases, hepatitis B and C may not cause any obvious symptoms for years. If they do appear, hepatitis B usually produces signs within 6 weeks to 6 months. Hepatitis C symptoms may appear as early as 2–6 weeks, but can sometimes take as long as 6 months.
A blood test can look for both types of hepatitis. The hepatitis B testing window is 3–6 weeks, while the hepatitis C testing window is 2–6 months. Early testing at 2 months may miss some cases, so a doctor may recommend retesting at 6 months.
A doctor can test for trichomoniasis with a swab of the rectum, penis, or vagina. Many people do not have symptoms, but some may notice a discharge or burning sensation within 5–28 days of exposure. It is possible to get a positive test within a week of exposure, though some people need to wait up to a month.
Syphilis usually begins with a sore on the genitals called a chancre. Blood tests can detect the bacteria within 1–2 weeks after the chancre appears. Chancres are typically painless and usually develop within 3 weeks of exposure, so the total testing window is about 4 weeks.
Because the development of syphilis varies from person to person, doctors often recommend retesting about 3 months after exposure.
Some STIs live in the body for many years without triggering any symptoms. Doctors may refer to them as dormant, meaning a person can never diagnose themselves based on symptoms alone.
This also means if a person is untested, they can unknowingly pass a dormant STI on to a sexual partner.
Examples of STI that can lay dormant include HIV, herpes, hepatitis C, chlamydia, syphilis, and HPV
The CDC recommend that all sexually-active adults with new or multiple partners seek testing for most STIs at least once per year.
STI testing, even for incurable infections, can save lives. It also slows the spread of STIs. Some benefits of testing are below:
- Some STIs are easier to treat if a doctor catches them early.
- Early STI testing can prevent a person from spreading an infection to their partners.
- A person can have an STI without knowing it.
- Some untreated STIs can cause serious health issues, such as cancer and pelvic inflammatory disease.
The right STI testing depends on many factors, including a person’s medical history, sexual history, risk of exposure, and prior history of STI tests.
It is important for people to regularly test for STIs, particularly if they have sex with multiple partners.
Early detection can make treatment easier and possibly prevent serious health issues. To reduce the risk of STIs, people should also practice safer sex techniques, such as using a condom.