Testing for specific STIs

See these guidelines for STI testing for specific sexually transmitted infections (STIs).

Chlamydia and gonorrhea

National guidelines recommend that you get screened annually if:

• You're a sexually active woman under age 25
• You're a woman older than 25 and at risk of STIs — such as having sex with a new partner or multiple partners
• You're a man who has sex with men
• You have HIV
• You've been forced to have intercourse or engage in sexual activity against your will

Doctors screen people for chlamydia and gonorrhea by taking a urine test or a swab inside the penis in men or from the cervix in women. The sample is then analyzed in a lab. Screening is important, because if you don't have signs or symptoms, you may not know that you have either infection.

HIV, syphilis and hepatitis

The Centers for Disease Control and Prevention (CDC) encourages HIV testing, at least once, as a routine part of medical care if you're an adolescent or adult between the ages of 13 and 64. Younger teens should be tested if they have a high risk of an STI. The CDC advises yearly HIV testing if you're at high risk of infection.

The CDC recommends hepatitis C screening for everyone born between 1945 and 1965. The incidence of hepatitis C is high in this age group, and the disease often has no symptoms until it's advanced. Vaccines are available for both hepatitis A and B if screening shows you haven't been exposed to these viruses.

National guidelines recommend that you request testing for HIV, syphilis and hepatitis if you:

• Test positive for another STI, which puts you at greater risk of other STIs
• Have had more than one sexual partner (or if your partner has had multiple partners) since your last test
• Use intravenous (IV) drugs
• Are a man who has sex with men
• Are pregnant or planning on becoming pregnant
• Have been forced to have intercourse or engage in sexual activity against your will

Your doctor tests you for syphilis by taking either a blood sample or a swab from any genital sores you might have. The sample is examined in a lab. A blood sample is taken to test for HIV and hepatitis.

Genital herpes

No good screening test exists for herpes — a viral infection. Most people with herpes infection never have any symptoms but can still transmit the virus to others. Your doctor may take a tissue scraping or culture of blisters or early ulcers, if you have them, to be examined in a lab. But a negative test doesn't rule out herpes as a cause for genital ulcerations.

A blood test also may help detect a past herpes infection, but results aren't always definite. Some blood tests can help differentiate between the two main types of the herpes virus. Type 1 is the virus that more typically causes cold sores, although it can also cause genital sores.

Type 2 is the virus that causes genital sores more often. Still, the results may not be totally clear, depending on the sensitivity of the test and the stage of the infection. False-positive and false-negative results are possible.

HPV

Certain types of human papillomavirus (HPV) can cause cervical cancer while other varieties of HPV can cause genital warts. Many sexually active people become infected with HPV at some point in their lives, but never develop symptoms. The virus typically disappears within two years.

There's no routinely used HPV screening test for men, in whom the infection is diagnosed by visual inspection or biopsy of genital warts. In women, HPV testing involves:

• Pap test. Pap tests, which check the cervix for abnormal cells, are recommended every three years for women between ages 21 and 65.
• HPV test. Women older than age 30 may be able to have the HPV test along with a Pap test every five years if previous tests were normal. Women between 21 and 30 will be given an HPV test if they've had abnormal results on their Pap test.

HPV has also been linked to cancer of the vulva, vagina, penis, anus, and mouth and throat. Vaccines can protect both men and women from some types of HPV, but they are most effective when administered before sexual activity begins.