Mycoplasma Genitalium Testing: What an Mgen Test Detects

What Is Mycoplasma Genitalium

Mycoplasma genitalium, often shortened to Mgen, is a bacterium that infects the cervix, the urethra, or the rectum. It spreads through vaginal or anal sex without a condom, and researchers are still studying whether oral sex passes it along. Many infections produce no symptoms at all, which makes the infection easy to miss.

When symptoms do appear, they can include discharge, burning with urination, or pelvic discomfort. Because these signs overlap with other infections, a lab test is the only way to know whether Mgen is the cause.

Mgen is not the same as Mycoplasma hominis or ureaplasma, which are different organisms covered by a separate test. Because the symptoms overlap so much, ordering the correct test matters.

Who Should Get Tested

Routine screening for Mgen is not recommended. Testing is most useful for people who have ongoing or returning symptoms after treatment for another infection, such as persistent urethritis in men or cervicitis in women.

• Men with recurrent urethritis after standard treatment
• Women with recurrent cervicitis
• People being evaluated for pelvic inflammatory disease
• Partners of someone who tested positive

Testing people without symptoms can lead to unnecessary antibiotics, which is one reason guidelines limit who should be screened. If you are the partner of someone with a confirmed Mgen infection, testing is reasonable even without symptoms, because reinfection is common and treatment is more likely to succeed when both partners are managed together.

How the Mgen Test Works

The preferred method is a nucleic acid amplification test, or NAAT, which detects the bacterium's DNA. The sample type depends on your anatomy. Men usually provide a first-catch urine sample, while women typically provide a vaginal or cervical swab.

A first-catch urine sample means you collect the first part of your stream, because that portion carries the most cellular material from the urethra. Holding your urine for about an hour before the sample can improve the result.

Vaginal swabs generally detect more infections than urine in women, so the sample type your clinician chooses can affect sensitivity. Tell the collection staff about any antibiotics you have taken recently, since they can lower the chance of detection.

The Window Period and Accuracy

Because Mgen testing detects the bacterium directly rather than antibodies, the window period is shorter than for blood tests. The exact timing is not firmly established, but waiting at least one to two weeks after a possible exposure reduces the chance of a false negative.

NAATs are sensitive and specific when the correct sample type is used. A test performed too early, or on the wrong sample, is the most common reason for an unreliable result. If your first test is negative but symptoms continue, a clinician may repeat the test or look for other causes rather than assume you are clear.

Antibiotic Resistance and Results

Mgen has developed resistance to several antibiotics, and cure rates with some older regimens have fallen. CDC advises resistance-guided therapy when a resistance test is available, because it improves the chance of clearing the infection on the first attempt.

If you test positive, a clinician will choose a treatment plan and may recommend a test of cure afterward. A positive result should always be discussed with a healthcare provider rather than self-treated.

How to Order and Where to Get Tested

You can order an Mgen test online and complete the sample at a partner lab. The steps are:

1. Select the Mycoplasma genitalium test or a combined mycoplasma and ureaplasma test.
2. Pay online and receive your lab order.
3. Provide a urine sample or swab at a nearby collection site.
4. Read your confidential results online in a few business days.

No doctor visit is required to start, though you should share a positive result with a clinician who can manage treatment.

How Much Does Testing Cost

Direct-access Mgen testing typically costs about $100 to $200, depending on the lab and the sample method. A combined mycoplasma and ureaplasma test sometimes costs only slightly more than Mgen alone.

Insurance may cover testing when it is ordered for symptoms, but paying directly keeps the process private and does not require a referral. Because treatment requires a prescription, budget for a follow-up visit as well as the test itself. Confirm the current price before you order, since lab fees can change.