True/False MCQ · Genital Tract and Sexually Transmitted Infections
Concerning the laboratory diagnosis of sexually transmitted infections, the following statements are correct:
- ANAAT is used to diagnose Chlamydia trachomatis and Neisseria gonorrhoeae
- BAn endocervical swab is inappropriate for diagnosing gonococcal cervicitis
- CA self-collected vaginal swab is an acceptable specimen for NAAT
- DFirst-void (voided) urine in men can be used for chlamydia/gonorrhoea NAAT
- EDark-ground microscopy is the test of choice for chlamydia
Show answers and explanation
- A. True
- B. False: An endocervical swab is appropriate for gonococcal cervicitis (gonorrhoea causes cervicitis).
- C. True
- D. True
- E. False: Dark-ground microscopy is for syphilis, not chlamydia (which is diagnosed by NAAT).
Laboratory diagnosis of STIs
NAAT and specimens
- NAAT is the test of choice for Chlamydia trachomatis and Neisseria gonorrhoeae.
- Acceptable specimens: cervical/urethral swabs, first-void (voided) urine in men, and self-collected vaginal swabs.
- Gonorrhoea causes cervicitis, so an endocervical swab IS appropriate (a posterior-fornix high vaginal swab is for vaginitis).
Other tests
Culture and serology are also used; dark-ground microscopy is for syphilis, not chlamydia.
Why A is true
NAAT diagnoses chlamydia and gonorrhoea.
Why B is false
An endocervical swab is appropriate for gonococcal cervicitis.
Why C is true
A self-collected vaginal swab is acceptable for NAAT.
Why D is true
First-void urine in men is acceptable for NAAT.
Why E is false
Dark-ground microscopy is for syphilis, not chlamydia.
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