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  2. West of Scotland Sexual Health Clinical Guidelines [in development]
  3. Sexually transmitted infections (STIs)
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  5. Chlamydia
  6. Symptoms and diagnosis

Symptoms and diagnosis

Warning

Symptoms and signs

Men:

  • asymptomatic in over 50%
  • urethral discharge
  • dysuria

Women:

  • asymptomatic in up to 90%
  • increase in vaginal discharge
  • dysuria
  • deep dyspareunia
  • post coital, intermenstrual bleeding or breakthrough bleeding
  • lower abdominal pain
  • mucopurulent cervicitis with or without contact bleeding
  • pelvic tenderness
  • cervical motion tenderness

Rectal Infections

  • Usually asymptomatic but may cause anal discharge and anorectal discomfort

Rates of rectal infections in MSM have been estimated at between 3% and 10.5%. Some studies in women report high rates (up to 77.3%) of concurrent urogenital and anorectal infection. Other studies however, report lower rates. Not all women with rectal chlamydia report anal sex. Further studies are needed to ascertain the utility of targeted versus routine rectal sampling in women.

Pharyngeal Infection

  • Usually asymptomatic

Rates of chlamydia carriage in MSM range from 0.5 to 2.3%. There is a paucity of good data on rates of pharyngeal infections in women.

Diagnosis of chlamydial infection

  • In all West of Scotland boards chlamydia testing is provided as a dual NAAT test for chlamydia and gonorrhoea using a variety of platforms.
  • Good sample collection technique improves sensitivity.
  • Patients presenting within two weeks of an exposure giving rise for concern should be asked to return for testing / retesting two weeks after the exposure.

 

Genital

Pharyngeal (all NAAT tests unlicensed)

Rectum (all NAAT tests unlicensed)

Males

First void urine

Offer pharyngeal swab to all MSM

Offer rectal swab to all MSM

 

Females

Vulvovaginal swab (several studies indicate that vulvovaginal swab sensitivities are greater than those of cervical swabs).
First Void Urine in females has lower sensitivity for the diagnosis of chlamydia and GC compared to other specimens so is not recommended.
Urethral swab in women who have undergone hysterectomy (in addition to vulvovaginal swab)

 

If anal intercourse has taken place

Blind swab if no rectal symptoms

 

Proctoscopy if rectal symptoms

 

Instructions for specimen collection

Urine

20ml first void urine (NB: technique should be carefully explained to patient, to ensure that the correct sample is obtained) in a plain universal container. The patient must not have urinated for at least one hour (or 2 hrs for some kits).  NB: Do not insert urinalysis dipsticks in the sample, as it may introduce contamination and adversely affect the amplification process.

Vulvovaginal swab

This may be self taken by patient (self obtained vulvovaginal swab (SOLVS)) or by the clinician. Insert the dry swab approx 5 cm into the vagina and gently rotate the swab for 10 to 30 seconds.  Bleeding may reduce sensitivity.

Pharyngeal swab

Rub the swab over the posterior pharynx and tonsillar crypts.

Rectal swab

  • Proctoscopy: the swab should be rubbed against the rectal wall.
  • Blind: the swab should be inserted 3cm into the anus and rotated once, gently pushing upwards and keeping in place for 10-30 seconds.

Editorial Information

Last reviewed: 01/05/2024

Next review date: 01/09/2026

Author(s): West of Scotland Managed Clinical Network for Sexual Health Clinical Guidelines Group.

Version: 8.2

Approved By: West of Scotland Managed Clinical Network for Sexual Health

Reviewer name(s): George Laird.