Any person who has sex can get an STI. Your risk increases if:

• You have more than 1 partner. The more partners you have, the greater your risk.

• Your partner has other partners. If your partner is exposed to an STI, you could be, too.

• You or your partner have had sex with other people in the past. Either of you might be carrying an STI from an earlier partner.

• You have an STI. The STI may cause sores or other health problems that increase your risk for new infections. Your risk will stay high unless you are treated for your current STI and change the behaviors that put you at risk.

Left untreated, certain STIs can be very painful or can lead to cancer or, rarely, death. Some can harm unborn babies whose mothers are infected. Others can cause you to not be able to have children (sterility) or can affect changes in behavior or your ability to think. You can prevent these problems with safer sex, regular checkups, and early treatment. Always use a latex condom when you have sex. Get tested if you’re at risk. And get treated early if you have an STI.

The only sure way to know if you have an STI is to get checked by a healthcare provider. If you notice a change in how your body looks or feels, have it checked out. But keep in mind, STIs don’t always show symptoms. So if you’re at risk for STIs, get checked regularly. If you find you have an STI, have your partner get treatment. If not, their health is at risk. And left untreated, your partner could pass the STI back to you, or on to others.

Be alert to any changes in your body and your partner’s body. Symptoms may appear in or near the vagina, penis, rectum, mouth, or throat. They may include:

• Unusual discharge

• Lumps, bumps, or rashes

• Sores that may be painful, itchy, or painless

• Itchy skin

• Burning with urination

• Pain in the pelvis, belly (abdomen), or rectum

• Bleeding from the rectum

You may have an STI even if you don’t have symptoms. If you think you are at risk, get checked. Go to a clinic or to your healthcare provider. If your partner has an STI, you need to be tested even if you feel fine.

Vaccines are available to prevent hepatitis A and hepatitis B. These are 2 kinds of STIs. There is also a vaccine to prevent human papillomavirus (HPV). This is a virus that can be passed from person to person through sexual contact. Ask your healthcare provider whether any of these vaccines is right for you.

Be alert to any changes in your body and your partner's body. Symptoms of an STI may appear in or near the vagina, penis, rectum, mouth, or throat. They may include:

• Abnormal discharge
• Lumps, bumps, or rashes
• Sores that may be painful, itchy, or painless
• Burning feeling or pain when you pee
• Pain in the pelvis, belly (abdomen), or rectum
• Bleeding or abnormal discharge from the rectum
• Pain during sex
• Painful periods
• Testicular pain

Your healthcare provider will take a health history and examine you. You'll be asked about your sex habits, such as sexual partners, condom use, and types of sex (vaginal, anal, oral) you have. You may also be asked about other risky behaviors, like drug use or past STIs. Give honest answers. Your provider will then check your body for signs of STIs. You may also need 1 or more of these tests:

• Swabs may be taken from the vagina, penis, mouth, or rectum. Sometimes you can collect the swab yourself. If you would be more comfortable doing that, ask your provider. The samples are then tested for STIs like chlamydia, gonorrhea, and trichomonas.

• Fluid may be swabbed from open sores.

• Urine samples may be taken. They're checked for bacteria or parasites that cause STIs, such as chlamydia, gonorrhea, and trichomonas.

• Blood samples may be taken. They're checked for viruses or bacteria that cause STIs, such as such as HIV, hepatitis, and syphilis.

• For women, cells from the cervix are checked for signs of cancer and the genital wart virus (HPV or human papillomavirus infection). This is called a Pap test. It is often now done along with HPV testing. If cell changes are found, or a high-risk type of HPV is found, a magnifying scope may be used to take a closer look (colposcopy).

• A Pap test may be done on the anus. This is to check for HPV-linked cancer or precancer changes. The provider gently swabs cells from the lining of the anus. This sample is then sent to a lab to be checked under a microscope. If there are any abnormal signs, you may need more testing.

Treatment depends on the type of STI you have. Common treatments include antibiotics. These may be pills, liquids, or shots (injections). Creams and gels can be put on sores or warts caused by certain STIs. Follow the tips below:

• Get new treatment for each new STI.

• Don’t use old medicine, even for the same STI. Use medicines as directed.

• Don’t share medicine unless instructed to do so by your healthcare provider or clinic.

• Take treatment for as long as your provider advises. If any side effects appear, contact your provider. Ask them what to do about it.

• Prevent future STIs by having safe sex practices.

• Don't have sex until you and your partner have completed treatment.

If you have an STI, it’s your duty to tell all your recent sex partners so they can be tested and treated. This is one important way to prevent the disease from being spread. Telling a partner that you have an STI can be hard. You may be embarrassed, angry, or afraid. It’s often unclear who had the STI first. So try not to place blame. Your healthcare provider may have some advice on how to start. If you do not feel comfortable telling your sex partner(s) about an STI, there are ways to inform your sex partner(s) anonymously. Ask your healthcare provider how to do this.

Even after you’ve been treated, you can still be infected again. This is a common problem. It can happen if a partner passes the STI back to you. To prevent this, any partners you have must be tested. They may also need treatment. After treatment, go to any scheduled follow-up visits. Then prevent future problems by practicing safer sex. Limit your number of partners. And always use a latex condom.

Remember that HIV is also an STI. If you have one type of STI, you can get others, including HIV. Ask your healthcare provider if you should take medicine to prevent getting HIV. This can be taken before the risk of exposure (PrEP or pre-exposure prophylaxis). Or it can be taken within 72 hours after unsafe sex (PEP or post-exposure prophylaxis).

GC test, gonorrhea nucleic acid amplification test (NAAT), gonorrhea DNA probe test

Gonorrhea is a sexually transmitted infection (STI) caused by N. gonorrhoeae. This test looks for DNA of gonorrhea bacteria. It is done on a sample taken from the cervix, urethra, penis, or rectum.

The samples are sent to a special lab where millions of copies of the DNA are made. An advantage of this test is that it can tell gonorrhea bacteria from chlamydia bacteria. Chlamydia is another common STI. This is important because chlamydia and gonorrhea cause the same symptoms.

You may have this test if you have certain risk factors that increase the chance of gonorrhea infection. You may also have this test if your healthcare provider thinks that you have gonorrhea.

Females with gonorrhea often have no symptoms. Those with symptoms may have:

• Vaginal discharge

• Burning feeling when urinating

• Bleeding between periods

• Pelvic pain

If you are pregnant, you may also be checked for gonorrhea as part of prenatal testing. That's because gonorrhea can be passed to the baby during delivery. This may cause blindness or a blood infection that can cause death. Finding and treating gonorrhea prevents these problems.

Males also may not have symptoms. If symptoms happen, they may include:

• Fluid leaking from the penis

• Pain when urinating

• Painful or swollen testicles

Your healthcare provider may take a sample from your genital region (vagina, cervix, or urethra). If you have had anal or oral sexual contact, your provider may do either a rectal or throat culture, or possibly both. A sample of urine may also be checked. You may also have lab tests to check for other STIs.

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

Normal results are negative, meaning that the lab found no evidence of gonorrhea.

If you test positive for gonorrhea, you'll be started on treatment to cure the disease. If left untreated, gonorrhea can cause severe reproductive and other health problems. Your sexual partners should be tested and treated as well.

Your healthcare provider will use a sterile, cotton-tipped swab to take a sample from the area to be tested. The swab will be moved from side to side to collect cells. Healthcare providers often swab from more than one area. In other cases, you may be given instructions to collect your own samples. Or a urine sample may also be tested.

If you are providing a urine sample, urinating within 1 to 2 hours of testing may affect the results. Taking antibiotics can also affect your test results. If you are female, your test results could be affected by douching or using vaginal creams within 24 hours of testing.

You don't need to prepare for this test. But females shouldn't douche or use vaginal creams within 24 hours of testing. For urine testing, you should not urinate within 1 to 2 hours of the test. In addition, be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.

C. trachomatis test, CZ test, chlamydia test

This test looks for Chlamydia trachomatis bacteria in a sample of cells collected by your healthcare provider.

C. trachomatis bacteria cause chlamydia. Chlamydia is 1 of the most common sexually transmitted infections (STIs) in the U.S.

The CDC recommends that sexually active women 25 and younger, as well as older women with risk factors, be screened once a year for chlamydia. That's because as many as half of women who get chlamydia don't have any symptoms. Men should be tested as soon as they have symptoms or if their partners are diagnosed with chlamydia.

In women, chlamydia may lead to cervicitis, an inflammation and swelling of the cervix. If it isn't treated, it can lead to serious sexual health problems, including infertility. Affected women may also develop endometriosis. In men, chlamydia can cause urethritis. This is a swelling of the urethra and possibly blood in the urine. Babies born to mothers infected with chlamydia can get a lung or eye infection.

Chlamydia can be treated with antibiotics.

You may need this test if you are a sexually active woman age 25 or younger, an older woman with risk factors, such as new or multiple sexual partners, or a man whose partner has been diagnosed with chlamydia. 

When symptoms happen in women, they can include:

• Abnormal vaginal bleeding or discharge

• Stomach pain

• Pain during sex

• Pain when urinating

• Rectal pain

When symptoms happen in men, they can include:

• Watery discharge from your penis that's not urine

• Pain when urinating

• Swollen scrotum

• Painful sensation in your testicles

• Rectal pain

Your healthcare provider may also order other tests because chlamydia symptoms can be confused with symptoms of other STIs. These STIs include:

• Gonorrhea 

• HIV/AIDS

• Hepatitis B

• Trichomoniasis

• Syphilis

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

Normal results are negative, meaning that no chlamydia cells were found in your sample.

A positive result means that chlamydia bacteria were found and that you are likely infected with the disease.

This test is done with a sample of cells from the urethra in men or the vagina in women. For men, the healthcare provider will gently insert a swab 3 to 4 centimeters into the urethra. The provider will turn it once to collect cells. For women, the provider will put the swab into the vagina to take cells from the cervix.

This test poses no known risks.

Other factors aren't likely to affect your results.

You don't need to prepare for this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use. 

Chlamydophila pneumoniae (C. pneumoniae) (swab), throat culture, pneumonia testing

If your healthcare provider suspects you have C. pneumoniae, they may do a swab test of your nose or throat to test for it. C. pneumoniae is just 1 of many types of bacteria that can cause pneumonia. 

You may need this test because you have a bacterial pneumonia, such as C. pneumoniae. This can be potentially life-threatening if not treated. Symptoms may look like a common cold at first. You may have chest congestion, runny nose, and sore throat. But these symptoms can get worse over time. If the infection isn't treated, you may even end up in the hospital. The C. pneumoniae bacteria can't be found by looking through a microscope, so your healthcare provider needs a culture to find out exactly which bacteria you have. This means lab technicians grow and identify the specific bacteria from your sample so your provider can prescribe the right treatment.

Blood tests are sometimes used to identify C. pneumoniae. If your healthcare provider isn't sure of the cause of your infection, you may be tested for other bacteria, too. 

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

The best result of a culture is to find no trace of bacteria. If the culture grows bacteria, then technicians can figure out which types of bacteria are there. The best treatment can then be prescribed. 

Your healthcare provider can take a sputum (phlegm) sample. Or your provider can rub a cotton swab in the back of your throat or nose to collect a sample for culture. The swab is taken to the lab, where the culture is grown to find out what germ is causing your illness.

This test poses no known risks. 

Other bacteria or germs found in your mouth and throat can cause problems in getting an accurate culture from a throat swab. It can also take a while to get back your test results. It often takes 1 to 3 weeks. For this reason, other tests, including blood tests, are often done to check for the cause of pneumonia. This way treatment can be started more quickly. But a blood test is not as accurate as a culture.

No preparation is needed for the test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use. 

A herpes sore may first look like a small white blister. The fluid inside the blister is filled with the herpes virus. At this stage, the virus sheds easily. This means it can be passed to other people.

A soft wet sore may form in place of the blister. The herpes virus is in the fluid of the open sore. So the virus can still be spread to others.

A soft crust forms as a new layer of skin grows. Fewer copies of the virus are present in the sore. The virus can still be passed to others.

The skin surface is normal. But the virus stays in the body. Shedding is less likely. But it can still occur.

If your healthcare provider thinks you may have herpes, you may need tests done. Tests like these can confirm the diagnosis:

• Viral culture. A small amount of fluid is swabbed from the base of a blister. The fluid is grown in a special culture with healthy cells. If herpes is present, it will change how the cells look.

• Fluorescent antibody test. Cells are taken from the base of a blister. They are stained and checked under a microscope. If herpes is present, the cells will change color.

• Molecular amplification. A sample of fluid that may have herpes virus is mixed with chemicals. These chemicals let pieces of the virus multiply very fast. These viral pieces can be found very quickly.

• Other tests. If you don't have sores, tests can be done on blood or cell samples. These tests may show if you carry the herpes virus. But they are the least accurate of all the tests.