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Trichomonas Testing

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Also known as: T. vaginalis; Wet Prep
Formal name: Trichomonas vaginalis; Trichomonas vaginalis RNA; Trichomonas vaginalis Culture; Trichomonas vaginalis DNA Probe; Trichomonas vaginalis by Amplified Detection; Trichomonas vaginalis by Direct Fluorescent Antibody (DFA)

At a Glance

Why Get Tested?

To diagnose an infection with the parasite Trichomonas vaginalis, which causes the sexually transmitted disease trichomoniasis

When to Get Tested?

When a woman has symptoms of infection, such as a foul-smelling vaginal discharge, genital itching, and/or pain during urination, or when a man has genital itching or irritation, burning after urination or ejaculation, and/or a discharge from the urethra

Sample Required?

In women, a swab of vaginal or cervical secretions; in men, a urethral swab. In some cases, urine may be tested.

Test Preparation Needed?


The Test Sample

What is being tested?

Testing can detect an infection with Trichomonas vaginalis, a microscopic, single cell (protozoan) parasite that is usually transmitted sexually, causing vaginal infections in women and urethral infections (urethritis) and prostatitis in men.

According to the Centers for Disease Control and Prevention (CDC), trichomoniasis, which is caused by the infection, is the most common, curable sexually transmitted disease (STD). In the U.S., an estimated 3.7 million people have the infection, but only about 30% develop any symptoms. Symptoms are more common in women than in men.

Trichomonas vaginalis is one of the most common causes of vaginitis (inflammation of the vagina) in women. When they occur, symptoms include:

  • Vaginal swelling
  • Itching, irritation, soreness
  • Burning sensation
  • Frothy, yellow-green vaginal discharge
  • Foul-smelling vaginal discharge
  • Frequent urge to urinate
  • Possible blood-spotting

In men, symptoms may include:

  • Burning after urinating or ejaculating
  • Itching or irritation of the urethra
  • Discharge from the urethra

These symptoms may take 5 to 28 days after exposure to an infected person or longer to develop; however, once diagnosed, trichomoniasis is easily treated with prescription antibiotics. During treatment, an infected person should cease sexual activity and inform partners so that they can also be treated and prevent re-infection.

How is the sample collected for testing?

In women, a swab of secretions is collected from the vagina. The sample may be obtained from the same thin-layer collection vial used for a Pap smear. In men, a swab is inserted into the urethra. Urine samples may also be used.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Centers for Disease Control and Prevention. Trichomoniasis - CDC Fact Sheet. Available online at through Page last updated August 3, 2012. Accessed January 2013. 

Centers for Disease Control and Prevention. Sexually Transmitted Disease Treatment Guidelines. Available online at through Page last reviewed January 28, 2011. Accessed January 2013.

American Sexual Health Association. Trichomoniasis. Available online at through Copyright 2012. Accessed January 2013.

MedlinePlus Medical Encylopedia. Trichomoniasis. Available online at Accessed January 2013.

Mission Pharmacal Company. Trichomoniasis: The most common curable sexually transmitted disease. Available online at through Copyright 2013. Accessed January 2013.

Arup Laboratories. Laboratory Test Directory. Available online through Accessed April 2013.

Quest Diagnostics. Test Center.  Available online through Accessed April 2013.

Sources Used in Previous Reviews

Centers for Disease Control and Prevention: Trichomonas Fact Sheet. Available online at through

American Social Health Association: VAGINITIS/TRICHOMONIASIS, Questions & Answers. Available online at through

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 1618.

Planned Parenthood: Trichomoniasis. Available online at through Accessed June 2009.

Centers for Disease Control and Prevention. Fact Sheet: Trichomoniasis. Available online at through Accessed June 2009.

American Social Health Association: VAGINITIS/TRICHOMONIASIS. Available online at through Accessed June 2009.

MedlinePlus Medical Encylopedia: Trichomoniasis. Available online at Accessed June 2009.

TeensHealth: Trichomoniasis. Available online at through Accessed June 2009.

Petrin D, Delgaty K, Bhatt R, et. al. Clinical and microbiological aspects of Trichomonas vaginalis. Clin Microbio Rev 11:300-317, 1998.

Briselden AM, Hiller SL. Evaluation of Afirm VP microbial identification for Gardnerella vaginalis and Trichomonas vaginalis. J Clin Microbiol 32:148-152, 1994.

DeMeo LR, Draper DL, McGregor JA, et. al. Evaluation of deoxyribonucleic acid probe for the detection of Trichomonas vaginalis in vaginal secretions. Am J Obstet Gynecol 174:1339-1342, 1996.

Rubino S, Muresu R, Rappelli P, et. al. Molecular probe for identification of Trichomonas vaginalis DNA. J Clin Microbiol 29:702-706, 1991.

Witkin SS, Inglis SR, Polaneczky M, et. al. Detection of Chlamydia trachomatis and Trichomonas vaginalis by polymerase chain reaction in introital specimens from pregnant women. Am J Obstet Gynecol 175:165-167, 1996.

Campbell L, Woods V, Lloyd T, Elsayed S, Church DL. Evaluation of the OSOM Trichomonas rapid test versus wet preparation examination for detection of Trichomonas vaginalis vaginitis in specimens from women with a low prevalence of infection. J Clin Microbiol 2008 Oct; 46(10):3467-9.