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Trichomonas

Also known as: Trich
Formal name: Trichomonas vaginalis

At a Glance

Why Get Tested?

To diagnose an infection with Trichomonas vaginalis

When to Get Tested?

If you have symptoms of infection, including vaginal discharge or pain during urination

Sample Required?

A swab of secretions taken from the vagina in women or the urethra in men.
Frequency of testing: as symptoms warrant.

The Test Sample

What is being tested?

The test is looking for infection by Trichomonas vaginalis, a sexually transmitted, microscopic parasite that causes vaginal infections in women and urethritis in some men.

How is the sample collected for testing?

In women, a swab of secretions is collected from the vagina. In men, a swab is inserted into the urethra of the penis. Alternatively, the first portion of urine is collected for testing.

The Test

How is it used?

The secretions collected on the swab are examined under a microscope or cultured or tested using nucleic amplification testing to detect the presence of Trichomonas vaginalis. Nucleic amplification testing is used to detect the DNA of Trichomonas vaginalis in urine samples.

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When is it requested?

Your doctor may request the test if you complain of symptoms, such as vaginal discharge or pain on urination. If you have an infection with another sexually transmitted disease, your doctor might test for trichomonas as well.

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What does the test result mean?

A positive test indicates an infection that requires treatment with a course of antibiotics.

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Is there anything else I should know?

Trichomonas is one of the most common sexually transmitted diseases.

An infected person is at greater risk of getting other sexually transmitted diseases, so the doctor may want to test for these other infections also.

Trichomonas infection can affect pregnancy, contributing to premature birth and low birth weight. You should inform your doctor if you may be pregnant. The doctor may medically manage a woman who is infected and in her first three months of pregnancy differently.

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Common Questions

1.  What are the symptoms of a trichomonas infection?

In women, the most common symptoms include a foul-smelling or frothy green discharge from the vagina and itching or redness in and around the vagina. Other symptoms can include pain during sexual intercourse, discomfort or swelling in the lower abdomen or groin, and the frequent urge to urinate, often with pain and burning. However, 50% of women with Trichomonas vaginalis infections have no symptoms.

Most infected men have no symptoms but when they do, symptoms include discharge from the urethra, a frequent urge to urinate, and a burning sensation on urination.

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2.  How is trichomonas transmitted?

The parasite is transmitted through sexual contact.

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3.  How is it treated?

It is usually treated with an antibiotic called metronidazole. Most antibiotics created to treat bacterial infections will not be effective against this parasitic infection. All current sexual partners must be treated at the same time or the patient is likely to become re-infected.

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4.  How can it be prevented?

  • Abstain from sexual intercourse; or
  • Use a latex condom properly, every time you have sexual intercourse, with every partner.
  • Limit your sexual partners. The more sex partners you have, the greater your risk of encountering someone who has this or other STDs.
  • If you are infected, your sexual partner(s) should be treated. This will prevent you from getting reinfected.

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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.