Sexually transmitted infections are diseases spread by sexual contact. Some of the most common STIs are:

• Chlamydia.
• Genital herpes.
• Genital warts or human papillomavirus (HPV).
• Gonorrhea.
• Hepatitis B.
• Human immunodeficiency virus (HIV), which causes AIDS.
• Syphilis.
• Trichomoniasis.

Left untreated, some STIs can lead to serious problems. For example:

• Certain high-risk types of HPV can cause cervical cancer in women.
• Some STIs can be passed from a woman to her newborn, which can cause serious problems for the baby.
• Chlamydia and gonorrhea can cause pelvic inflammatory disease (PID) in women. PID can lead to serious problems, including not being able to have a baby (infertility).
• Syphilis can cause problems with pregnancy, nerve and heart problems, and death.
• Gonorrhea can increase the risk of bladder cancer in men.

Treatment is available for all sexually transmitted infections (STIs) to relieve symptoms, even if a cure isn't possible.

Some of the most common STIs—chlamydia, gonorrhea, and syphilis—are caused by bacteria and are treated and cured with antibiotics.

STIs caused by viruses, such as genital herpes and genital warts, aren't cured with antibiotics. But treatments are available to relieve symptoms.

Having a routine STI test means getting tested even though you don't have symptoms of an infection. Experts say that certain groups should be routinely tested for certain STIs. Some expert opinions may vary, and your doctor may recommend testing based on your personal history.

Chlamydia

The U.S. Preventive Services Task Force (USPSTF) recommends a chlamydia test for all high-risk nonpregnant and pregnant women.

You have a high risk of getting chlamydia if:

• You're a sexually active female who is younger than age 25.
• You've had chlamydia or other STIs before.
• You have a new sex partner or have had more than one sex partner in the past year.
• You don't use condoms when having sex, you use drugs, or you exchange sex for money.

Gonorrhea

The USPSTF recommends a gonorrhea test for all high-risk nonpregnant and pregnant women.

You have a high risk of getting gonorrhea if:

• You're a sexually active male or female younger than 25.
• You have had gonorrhea or other STIs before.
• You have a new sex partner or have had more than one sex partner in the past year.
• You have a high-risk partner. A high-risk partner has other sex partners, unprotected sex, or gonorrhea-infected sex partners.
• You don't use condoms when having sex, you use drugs, or you exchange sex for money.

Syphilis

The USPSTF recommends a syphilis test for all men and women at high risk and all pregnant women.

You have a high risk of getting syphilis if you:

• Are a man who has sex with men and has high-risk sexual behaviors.
• Are a sex worker or you exchange sex for drugs.
• Are in an adult prison or jail.

Tests for STIs are fairly simple. If you have a test for chlamydia or gonorrhea, a nurse or doctor will test for bacteria that cause the infections. You may have a urine test, or the doctor may take a sample of body fluid from the throat, inside the tip of the penis, or inside the rectum or vagina. A gonorrhea culture test also may be done to see if the bacteria are resistant to antibiotics.

A syphilis test looks for antibodies to the bacteria that cause syphilis. Your doctor may do a blood test or may test body fluid or tissue. A follow-up test may be done to confirm the infection.

Getting tested can help find an infection early or when you have no symptoms. This is important so that:

• You can get treatment and avoid long-term problems, such as not being able to have a baby (infertility).
• If you know that you have an STI, you can get treatment and avoid spreading the infection to others.
• If you know that you have an STI, you can tell your sex partner(s) so they can be treated and can avoid spreading the infection.
• If you're pregnant, an STI test can find an infection so you don't spread the infection to your newborn.

• If your test shows that you have an STI, your sex partner(s) will need to know and get tested, which may affect your relationship.
• If you have an STI, your doctor may be required by law to report it to your local health department. You may be asked for names and addresses of your sex partners.
• You could have a false-positive test result, which shows that you have the disease when you actually don't. This could cause you unneeded worry and treatment.
• For syphilis, you could have a false-negative result, which shows that you don't have the disease when you actually do. (Sometimes the test can't find the antibodies yet.) So you might infect others because you don't think you have the disease.

Your doctor may want you to be tested if:

• You have a high risk for getting an STI.
• You are pregnant.