What STIs Are Tested? 8 Commonly Tested STIs

Medically Reviewed on 2/11/2022
What STIs Are Tested
Commonly tested sexually transmitted infections (STIs) include chlamydia, syphilis, genital herpes, gonorrhea, AIDS, HPV, trichomoniasis, and hepatitis B

Sexually transmitted infections (STIs), also called sexually transmitted diseases (STDs) are common and affect more than a million people a year. STIs that are tested most often include chlamydia, syphilis, genital herpes, gonorrhea, acquired immunodeficiency syndrome (AIDS), human papillomavirus (HPV), trichomoniasis, and hepatitis B.

According to the World Health Organization, there are 20 known types of STIs and more than a million cases are registered every day worldwide.

STIs have a direct effect on reproductive and sexual health and can cause infertility, pregnancy complications, and cancer. Most cases of STIs are transmitted from someone who is asymptomatic and can cause symptoms such as vaginal discharge, urethral discharge, abdominal pain, and genital ulcers.

8 commonly tested STIs

1. Chlamydia

Chlamydia is caused by Chlamydia trachomatis, which infects the urethra, rectum, throat, or cervix. It is most commonly seen in young adolescents and adults. Chlamydia can be treated with proper medication and care. However, like most STIs, chlamydia can remain undiagnosed for several years, leading to worsening of the condition.

2. Syphilis

Syphilis is caused by Treponema pallidum, and the infection is divided into three stages:

  • Stage 1: Development of a hard, round sore called a chancre that forms in the genital area. This type of genital ulcer is usually painless and heals within a few days without medical treatment.
  • Stage 2: Development of red rash on the trunk that spreads over the entire body, including the palms and soles of the feet. If left untreated, the disease may progress to a latent infection that can last for years. 
  • Stage 3: May damage various organs such as the heart, liver, brain, joints, and eyes. 

If a pregnant woman is infected with syphilis, the bacterium can be transmitted to the fetus as well, causing congenital syphilis. This can increase the risk of miscarriage, fetal death, or death of the baby within a few days of birth.

3. Genital herpes

Genital herpes can be caused by two types of herpes simplex virus:

  • Herpes simplex type I virus: Causes cold sores outside or around the mouth and blisters in the throat and on the gums. 
  • Herpes simplex type II virus: Causes infections or rash on genital areas, buttocks, and thighs. 

Because the virus lives in the sensory nerves at the base of the spinal cord, genital herpes is a chronic condition. Although the virus remains dormant the majority of the time, flare-ups can cause clusters of ulcers. Herpes is extremely contagious, and it can be transmitted in the absence of any symptoms.

4. Gonorrhea

Gonorrhea is caused by Neisseria gonorrhoeae, which typically affects the urethra, rectum, throat, and cervix. The infection can be transmitted through vaginal, anal, or oral sex. Pregnant mothers can transmit the infection to their babies during childbirth. Rapidly proliferating bacteria can migrate to the fallopian tubes and uterus, causing pelvic inflammatory disease

Although gonorrhea symptoms are usually mild, immediate medical treatment is required because it can lead to scarring and inflammation of the fallopian tubes and ovaries. In extreme cases, it can cause sterility.

5. Acquired immunodeficiency syndrome (AIDS)

AIDS is caused by human immunodeficiency virus (HIV) and spreads the through the use contaminated needles or unprotected sex with an infected person. 

HIV affects the function of the T-helper lymphocytes, which are a type of immune cells. The T-cells are forced to produce copies of HIV that deplete the number of normal helper T-cells in the bloodstream, making the individual vulnerable to AIDS-related chronic conditions such as pneumocystis carinii pneumonia, HIV wasting syndrome, tuberculosis, candidiasis of the esophagus, and Kaposi's sarcoma.

6. Human papillomavirus (HPV)

HPV is the most common STI in the United States. Although in many cases it doesn’t cause symptoms, HPV is contagious and can be transmitted through unprotected sex.

HPV causes benign genital warts that appear in clusters around the vagina, cervix, penis, scrotum, and anus. Warts can be treated with topical ointments and heal easily, but they often return. Larger warts may need to be surgically removed. In some cases, HPV can cause cancers of the cervix, vagina, vulva, penis, or anus. Safe and effective vaccines are available to prevent HPV infection.

7. Trichomoniasis

Trichomoniasis is caused by a parasite and can spread through sexual contact. 

This condition can be easily treated with antibiotics. However, in most cases, only mild symptoms may occur, such as irritation or itchiness in the genital area or moderate to severe discomfort during sex.

8. Hepatitis B

Hepatitis B is an infection caused by the hepatitis B virus. The infection can spread through sexaul contact, blood transfusions, and childbirth

While the condition may not cause symptoms, if they do occur they may include fever, muscle ache, poor appetite, fatigue, diarrhea, and vomiting. Hepatitis affects the liver cells, and if left untreated can lead to cirrhosis, cancer, and even death. Hepatitis B can be prevented through safe and effective vaccines against this virus.


Condoms are the best protection from sexually transmitted diseases (STDs). See Answer

What are the risk factors for STIs?

Factors that increase the risk of STIs include:

  • Unprotected sex
  • Sex with multiple partners
  • Intravenous drug use

How are STIs treated?

Most STIs are chronic. However, treatment options are available that can help reduce symptoms:

  • Antibiotics: Antibiotics can effectively cure parasitic and bacterial STIs such as gonorrhea, trichomoniasis, syphilis, or chlamydia. Abstaining from sex for a period of time as advised by your doctor is necessary to heal warts and lesions.
  • Antiviral drugs: STIs such as herpes and HIV can be treated with antiviral drugs. Proper treatment is required to reduce the risk of transmission.

STIs can be prevented by practicing safe sex measures, such as the use of condoms and vaccination where possible.

Medically Reviewed on 2/11/2022
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