1. STDs
2. Gonorrhoea
3. Testing

Gonorrhoea Testing Singapore | Shim Clinic

Gonorrhoea Test is usually by

• Gonorrhoea PCR (polymerase chain reaction) test
• Gonococcal (GC) culture
• Gram-negative intracellular diplococci by gram stain smear

LABORATORY TESTS

• Presumptive diagnosis of gonorrhoea is made on finding Gram-negative intracellular diplococci in a smear of the discharge. In men, microscopy of urethral smears is more sensitive in symptomatic (90–95%) than in asymptomatic (50–75%) patients. In women sensitivity of microscopy of Gram-stained endocervical smears is around 50%. Microscopy is not appropriate for pharyngeal and rectal specimens.
• Confirmatory diagnosis is made by identification of the organism on selective culture media.
• NAATs (PCR) are more sensitive than culture and can be used as diagnostic/ screening tests on non-invasively collected specimens (urine and self-taken vaginal swabs). The sensitivity of NAATs is >90% for genital sites, whilst the sensitivity of culture may be < than 75% for endocervical swabs.
• There are currently no NAATs licensed for use with rectal or pharyngeal samples, although studies suggest that the sensitivity of NAATs at non-genital sites exceeds 90% whereas the sensitivity of culture can be <60% for rectal swabs and <50% for pharyngeal swabs.
• The DSC clinic currently uses NAATs to detect rectal, urethral and cervical GC, and cultures for pharyngeal GC.
• Some degree of caution is required in interpretation of positive results as the specificity of NAATs is not 100%; especially if the risk profile of the patient is at odds with the result. Confirmation of a NAAT positive result by culture can be considered in cases where there is some doubt. However, generally NAATs are considered reliable for detection.
• As nonculture tests cannot provide antimicrobial susceptibility results, in cases of persistent gonococcal infection after treatment, clinicians should perform both culture and antimicrobial susceptibility testing.
• Gonococcal complement fixation test (GC-CFT) should not be used for diagnosing gonorrhoea.

Specimen collection:

Males:

Routinely from the urethra; rectal and/or oropharyngeal tests when indicated by sexual activity. FVU provides an alternative urethral specimen for testing with a NAAT.

Females:

Routinely from endocervix if speculum examination performed; and rectal and oropharyngeal tests when indicated by the sexual history. Urine or a self-taken vaginal swab are suitable alternative specimens as screening tests using a NAAT.

References

• Gonorrhoea testing @ Wikipedia