At a glance

Also known as


Why get tested?

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

When to get tested?

When a woman shows symptoms of infection, such as a strong-smelling vaginal discharge, genital itching, and/or pain during urination, or if a man has the frequent urge to urinate and/or a discharge from the urethra.

Sample required?

In women, a swab of vaginal or cervical secretions; a sample may be obtained from the same thin-layer collection vial used for a Pap smear; in men, a urethral swab is required. Other sources may include urine or prostatic fluid.

Frequency of testing

As symptoms warrant or when sexual partners test positive.

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.

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


The Test

How is it used?

The secretions collected on the swab are examined under a microscope 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 and other samples.

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. Testing may also be performed if your partner has tested positive for a genital tract infection.

What does the test result mean?

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

Is there anything else I should know?

Trichomonas is an uncommon sexually transmitted disease in most parts of urban Australia. It is more common in Aboriginal populations especially in rural and remote communities.

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.

Common Questions

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.

How is trichomonas transmitted?

The parasite is transmitted through sexual contact. Transmission by non-sexual contact in young children in developing countries have also been reported.

How is it treated?

It is usually treated with an antibiotic called metronidazole. Most antibiotics used 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.

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.

Last Review Date: February 14, 2015