By Susan Gillespie, MD, PhD, FAAP
As a parent, it's important to keep communication open with your teen about their sexual health. If your teen is sexually active, they're at risk of getting sexually transmitted infections (STIs), also known as sexually transmitted diseases. STIs are common in the United States. They can be caused by bacteria such as chlamydia, gonorrhea and syphilis, along with viruses such as human immunodeficiency virus (HIV), human papillomavirus (HPV) and herpes simplex virus (HSV).
Getting tested for STIs is important when teens are sexually active. This is because STIs often have no signs or symptoms. Yet if they're left untreated, some of these infections can cause infertility and raise the risk of other infections. Routine testing is also important for pregnant people of all ages, since some STIs can cause stillbirth or lead to infection in the baby.
Here's what you need to know about diagnostic STI testing.
Human immunodeficiency virus (HIV)
Human immunodeficiency virus attacks the immune system. When it's left untreated, HIV can result in acquired immunodeficiency syndrome (AIDS).
There are three different tests used to diagnose HIV:
An antibody test uses saliva or blood to check for HIV antibodies. Self-tests and most rapid tests are this type.
An antigen/antibody test checks for both an antigen called p24 and HIV antibodies. This test also uses blood.
A nucleic acid test (NAT) looks for HIV in the blood. NATs aren't used for routine screenings because they're expensive.
Recommended testing frequency for HIV
The American Academy of Pediatrics (AAP) recommends at least one routine HIV screening for all teens ages 15 years and older. Sexually active teens should get tested at least every year after their first screening.
Teens that are higher risk may need to be tested more often. This includes males 13 years or older that have sex with other males; people whose sexual partner has HIV; and people who use injectable drugs.
In addition, pregnant people should be tested for HIV at their first prenatal visit. They should be tested again during the third trimester if they live in communities with high rates of HIV infection. Testing helps identify HIV infection early to prevent congenital (present at birth) HIV infection. Thanks to routine HIV testing during pregnancy, congenital HIV infections are much less common that they once were.
Chlamydia can affect both males and females. It's a fairly common STI. When it's left untreated, it can lead to severe damage to the female reproductive organs.
Nucleic acid amplification tests (NAATs) are the typical method of diagnosing chlamydia.
For females, your healthcare provider collects a sample from the vagina using a cotton swab. If preferred, your teen can do the swab themselves. Usually, for both males and females, urine can be used for this test. Sometimes, a sample collected from the cervix for females or the urethra for males can be used. If your teen has had oral and/or anal sex, they may need a swab taken from their throat and/or rectum.
Recommended testing frequency for chlamydia
Sexually active females under 25 years should be tested every year.
In areas with a high rate of chlamydia among males, sexually active males under 25 years should also be tested every year. Ask your doctor about this.
Males who are 13 years or older that have sex with other males should be tested yearly too.
Pregnant women of any age should be tested at their first prenatal visit.
Gonorrhea is another common STI, especially in people who are 15- to 24-years old. It affects both males and females.
As with chlamydia, NAATs are most frequently used to diagnose gonorrhea. In fact, the two diseases are often tested at the same time. Cultures are sometimes used too.
Usually, urine can be used for this test. If your teen has had oral and/or anal sex, they may need a swab taken from their throat and/or rectum. Sometimes, a sample from the cervix for females or the urethra for males is needed.
Recommended testing frequency for gonorrhea
Sexually active females under 25 years should be tested every year. Males who are 13 years or older that have sex with other males should be tested yearly too.
Pregnant women of any age should be tested at their first prenatal visit.
Though it's easily treated with antibiotics, syphilis can cause serious health complications if it stays untreated.
Doctors usually use a blood test to check for syphilis. Sometimes they use fluid from a syphilis sore instead.
Recommended testing frequency for syphilis
Males who are 13 years or older that have sex with other males should be tested every year.
Testing for syphilis during pregnancy also is important to prevent congenital syphilis infections, which have been rising sharply in the United States.
Pregnant people of any age should be tested at their first prenatal visit. Testing should also be done twice during the third trimester, at 28 weeks gestation and at delivery, for pregnant people who live in communities with high rates of syphilis.
Pelvic inflammatory disease (PID)
Pelvic inflammatory disease (PID) is caused by inflammation of a female's reproductive organs. Usually, this inflammation is caused by an untreated STI, such as chlamydia or gonorrhea. Other infections that aren't STIs can cause it too. Only females can get PID.
PID can be tricky to diagnose. There's not a specific test for it. Instead, doctors rely on what they find out from your child's
Genital warts/human papillomavirus (HPV)
In the United States, human papillomavirus (HPV) is the most common STI. There are many different kinds of HPV. For most people, an HPV infection goes away without treatment. In fact, people who have HPV usually don't know they do because they don't ever have symptoms.
When HPV doesn't go away, it can cause genital warts or cervical and other cancers. This is how some people find out they're infected. The types of HPV that cause genital warts aren't the same as the ones that can cause cancer.
If your teen has genital warts, your doctor will probably be able to diagnose HPV by looking at them. Sometimes, a sample is taken for lab testing.
There are HPV tests for screening cervical cancer. But these aren't recommended for males, adolescents, or females under the age of 30 years.
Genital herpes is another STI that's common in the United States. It can be caused by two types of viruses: herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2).
Most people don't know they have herpes because they have no symptoms. Or their symptoms are so mild, they don't notice. But even when you don't have symptoms, you can still spread it.
A herpes outbreak looks like blisters on the genitals. The blisters break open and turn into sores. These painful sores can take a week or longer to heal.
Like HPV, your child's doctor may diagnose genital herpes just by looking at the sores. They may test a sample from the sores. In certain cases, your doctor might do a blood test to look for HSV antibodies.
About Dr. Gillespie
Susan Gillespie, MD, PhD, FAAP, is an Associate Professor of Pediatrics at Baylor College of Medicine in Houston. At Baylor, she provides care to infants, children and adolescents exposed to or living with HIV. She also serves on local and regional committees advocating for children born to women living with HIV. Dr. Gillespie has an interest in global health and worked with the Baylor International Pediatric AIDS Initiative to provide HIV care to children living in several low- and middle-income countries, primarily in sub-Saharan Africa. Dr. Gillespie is Vice-Chair of Justice, Equity, Diversity and Inclusion for the Baylor Department of Pediatrics.