Explanation

Ureaplasma urealyticum PCR (urine): what is measured?

Ureaplasma urealyticum is a small bacterium without a cell wall that is present in the genital organs of many healthy people without causing symptoms (carriage). In adults, the bacterium is usually transmitted through sex, but it is not counted among the STIs. In a small share of men with urethritis (inflammation of the urethra), a large amount of this bacterium may possibly play a role. The PCR looks for genetic material of the bacterium in the first portion of urine and does not say whether the bacterium causes symptoms.

What can it detect?

Presence of Ureaplasma urealyticum in the urethra; this is usually carriage without symptoms

Result

What does the result mean?

Positive result

A positive result means that the bacterium is present. This is common in people without symptoms and usually does not mean disease. According to a position statement of the European STI Guidelines Editorial Board (IUSTI, 2018), in men with urethritis Ureaplasma urealyticum is in 40 to 80 percent of cases merely a bystander carrier and not the cause; in women there is no good evidence that the bacterium causes inflammation or infertility. According to this position statement, treatment of a positive result without symptoms is not needed; the bacterium is also hard to get rid of permanently.

Negative result

A negative result means that the bacterium was not found. Because Ureaplasma urealyticum also occurs in healthy people and is not a proven cause of disease, a negative result has little meaning for your health. This result does not explain or rule out urethral symptoms; tests for chlamydia, gonorrhea and Mycoplasma genitalium, among others, are intended for that.

After an abnormal result

With a positive result without symptoms, according to the European recommendation, no treatment or follow-up is needed. With symptoms, the GP first looks for other causes, such as chlamydia, gonorrhea, Mycoplasma genitalium or trichomonas; only in men with urethritis and a large amount of Ureaplasma urealyticum can treatment be considered, although the evidence for this is weak. Ureaplasma is not notifiable.

Reliability

How reliable is the test?

The PCR reliably detects the bacterium, but a positive result does not distinguish between carriage and an infection that causes symptoms. Ureaplasma urealyticum is not a proven cause of disease: the evidence that this bacterium causes urethritis or other symptoms is insufficient. As a result, a positive result says little, both in people without symptoms and in most people with symptoms.

What can affect the result?

A positive result does not say whether the bacterium causes symptoms; many people without symptoms also carry the bacterium.
The European recommendation only considers a large amount of bacteria in men with urethritis to be possibly meaningful; this result is positive or negative and says nothing about the amount.
Treatment with antibiotics often does not remove the bacterium permanently, and disappearance of the bacterium is not strongly linked to disappearance of symptoms.
If you urinated less than 1 hour before collecting the sample, or catch more than the first part of the stream, the sample is diluted and the test can miss an infection.

Preparation

Collect the urine when you have not passed urine for at least 1 hour.
Collect only the first part of the stream, not the middle part.

Who it is for

Who is the test useful for?

Useful for

The result usually does not explain symptoms, because the bacterium also occurs in many healthy people. Urethral symptoms more often fit chlamydia or gonorrhea, and, with symptoms lasting longer than 4 weeks, Mycoplasma genitalium or sometimes trichomonas. This test is not suitable for questions about pregnancy or fertility.

How common is it?

How common Ureaplasma urealyticum is in the Netherlands is not known, because it is not routinely tested for. In international studies using PCR, the bacterium was found in an estimated 5 to 15 percent of men aged 16 to 44 and in 5 to 20 percent of sexually active women who were not pregnant. Carriage is more common at a younger age and after a new sexual partner.

Horner et al., European STI Guidelines Editorial Board (IUSTI), 2018

Drawbacks and risks

A positive result can lead to unnecessary treatment with antibiotics, with a chance of side effects and of resistance in this bacterium and in other bacteria, including those that cause real STIs.
A positive result can wrongly give the idea that you have an STI, leading to worry or tension in a relationship.

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