STIs
Gonorroe / Neisseria gonorrhoeae PCR (swab)
PCR test for genetic material of the gonorrhea bacterium in a self-collected swab from the vagina, anus or throat.
What it measures
Gonorrhea (the clap) is an STI caused by the bacterium Neisseria gonorrhoeae. The PCR looks for genetic material of the bacterium in material that you collect yourself with a cotton swab from the vagina, the anus or the throat. In women, a self-collected deep vaginal swab is the first choice according to the LCI guideline (RIVM); in research, it found 96 to 100 in 100 infections. The result only applies to the site where the swab was taken.
- A current gonorrhea infection of the vagina and cervix, even if it causes no symptoms
- A gonorrhea infection of the anus or throat, which usually causes no symptoms
Positive
A positive result means that genetic material of the gonorrhea bacterium (Neisseria gonorrhoeae) was found, which fits a current infection. In men, gonorrhea of the urethra usually causes symptoms; in women and in the throat and anus, it often does not. Without treatment, gonorrhea can cause inflammation of the womb and fallopian tubes in women and inflammation of the epididymis or prostate in men; rarely, the bacterium spreads to the joints or blood. Gonorrhea can be treated with antibiotics, but the bacterium is increasingly becoming insensitive (resistant) to antibiotics.
Negative
A negative result means that no gonorrhea was found at the sampled site. Without symptoms, Thuisarts advises testing from 2 weeks after the last risk contact. According to the LCI guideline (RIVM), it is not known exactly how soon the test becomes positive after infection; an infection without symptoms can last for months, so testing is useful up to 3 months after a risk contact. The result says nothing about gonorrhea at another site on the body.
If your result is abnormal
With a positive result, according to the guideline the GP preferably also has a culture done to see which antibiotics the bacterium is sensitive to, and usually treats with a single injection of an antibiotic; this goes together with testing for other STIs such as chlamydia, HIV and syphilis and warning sexual partners from the past six months. After treatment with the standard drug, a follow-up test is usually not needed. Gonorrhea is not notifiable for individual cases.
Reliability
According to the LCI guideline (RIVM) and the multidisciplinary STI guideline, the PCR (NAAT) is the first choice for detecting gonorrhea: its sensitivity is higher than that of a culture, and the specificity on urine and vaginal material approaches 100 percent. In men, first-void urine is the recommended material; in women, a self-collected vaginal swab. A positive PCR says nothing about resistance; for that, the guideline advises a culture. Because the test detects genetic material, it can still be positive shortly after treatment.
Limitations
- Shortly after the risk contact, the test can miss an infection; without symptoms, the advice is to test from 2 weeks after the contact.
- With self-collection, too little material may end up on the swab, for example if it was not inserted far enough or for too short a time; this can give a falsely negative result.
- According to the LCI guideline, false-positive results can occur with throat and anal swabs, even with a high specificity.
- Up to about 2 weeks after treatment, the test can remain positive due to leftover genetic material.
How common is this
In 2024, the GGD's Centers for Sexual Health found gonorrhea in 13,952 people; GPs made the diagnosis about 18,800 times in 2023. Gonorrhea is diagnosed much more often in men than in women, especially in men who have sex with men. The number of diagnoses has been rising for more than ten years.
Who is this useful for
A vaginal swab is useful for women (and other people with a vagina) with symptoms such as changed discharge, bleeding between periods or pain when urinating, after sex without a condom with a new or changing partner, and if a sexual partner has gonorrhea. A throat or anal swab is useful after oral or anal sex or with symptoms at that site. According to the LCI guideline, men who have sex with men are routinely tested in the throat, anus and urethra.
Downsides and risks
- A false-positive result, especially with a throat or anal swab, can cause unnecessary worry and treatment.
- A negative result at one site can give false reassurance if there was also a risk at another site.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results