Investigation

Investigations of Chlamydial infection includes:

• testing for chlamydia should use nucleic acid amplification (1) - these tests provide a sensitivity approaching 100% (compared with 60-80% sensitivity with ELISA)
  • in women - first void urine, cervical swab and vaginal swab are all equally sensitive
    • a cervical swab or vulvovaginal swab are first-line choices
    • if speculum examination is not possible, urine specimens can be used (2)
  • in men - first void urine is the preferred test as it is more acceptable than a urethral swab

Other tests include:

• cell culture - expensive and difficult to culture
• immunofluorescence staining using monoclonal antibodies to the chlamydia antigen; reliable but technically-difficult

Recently, a new variant of chlamydia trachomatis (nvCT) has emerged in Sweden, and has been identified in some other countries including Scotland and Ireland. This variant may give false negative results in some nucleic acid amplification tests (NAAT) (3).

Reference:

• (1) SIGN. Management of genital Chlamydia trachomatis infection: a national clinical guideline. Edinburgh: Scottish Intercollegiate Guidelines Network, 2000.
• (2) BASHH (2006) 2006 national guideline for the management of genital tract infection with Chlamydia trachomatis. British Association for Sexual Health and HIV
• (3) SIGN. Management of genital Chlamydia trachomatis infection: a national clinical guideline. Edinburgh: Scottish Intercollegiate Guidelines Network March 2009