1. Microscopy
Gram negative intracellular diplococci
(NB Microscopy provides a provisional diagnosis – always make this clear. Final diagnosis is the result of the PCR and/or culture)
If microscopy not available on site, dry the slide on a hotplate/airdry and transport as per guideline for gram-stain and microscopy at local lab.
2. NAAT
Nucleic acid amplification testing (NAAT) is a new technique which facilitates less invasive testing and examination.
NAAT testing is emerging as the primary method of excluding gonorrhoea from ano-genital and pharyngeal sites (although not yet licensed for use in rectum and pharynx).
A positive result from a GC NAAT should always, with patient consent, have a culture swab by repeat sampling, prior to treatment and sending the specimen to the appropriate bacteriology lab for direct plating. This allows antibiotic susceptibility testing and resistant strains can be identified.
There is a small risk of false positives with NAAT testing. Counselling/ partner notification should take this into account, especially if the clinical likelihood is low.
The test sensitivity in female urine is significantly lower, therefore urine is not the optimal specimen in women.
3. Culture
When doing a culture for GC, a NAAT test (if available in your health board) should be performed at the same time. Culture is used for:
- Clinical locations where NAAT testing is unavailable
- Any genital or rectal discharge
- Suspected PID / cervicitis
- Contacts of gonorrhoea – prior to epidemiological treatment.
- Pharyngeal specimens (pending further validation).
- Rectal samples in men who have sex with men (MSM).
- Any NAAT-positive case with no previous culture performed (state on request that NAAT positive).
The following table shows which tests should be taken:
Please note that NAAT testing on rectal and pharyngeal swabs has not been validated. Microscopy, if available, should be done at symptomatic sites (cervix, urethra and rectal).
Anatomical site being tested
|
Type of specimen
|
Heterosexual male
|
Men who have sex with men
|
Female
|
Throat/ pharynx
|
Throat swab for GC/chlamydia NAAT
|
*
|
√
(if sexual history dictates or symptomatic at this site)
|
*
|
Throat swab for GC culture
|
*
|
*
|
*
|
Urethra
|
First void urine for GC/chlamydia NAAT
|
√
|
√
|
*
|
Charcoal urethral swab for GC culture
|
*
|
*
|
*
|
Female genital tract
|
Self obtained low vaginal swab for GC/chlamydia NAAT
|
N/A
|
N/A
|
√ (if asymptomatic and not being examined)
|
Endocervical charcoal swab for GC culture
|
N/A
|
N/A
|
*
|
Endocervical swab for GC/chlamydia NAAT
|
N/A
|
N/A
|
√If symptomatic at this site or being examined eg smear
|
Rectum
Perform proctoscopy if symptomatic
|
Rectal swab for GC/chlamydia NAAT
|
*
|
√
(if sexual history dictates or symptomatic at this site
|
*
|
Charcoal rectal swab for GC culture
|
*
|
*
|
*
|
*Take test if one or more of the following criteria are met. Client is:
- symptomatic from this site
- GC NAAT positive at this site
- gonorrhoea contact at this site
- post sexual assault and penetration has occurred in these sites.