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Finding, confirming, and managing gonorrhoea in a population screened for chlamydia using the Gen-Probe Aptima Combo2 assay
  1. S J Lavelle1,
  2. K E Jones2,
  3. H Mallinson3,
  4. A M C Webb4
  1. 1Liverpool and South Sefton Chlamydia Screening Programme, Liverpool L1 6AA, UK
  2. 2Department of GU Medicine, Royal Liverpool University Hospital, Liverpool, L7 8XP, UK
  3. 3Clinical Microbiology and Health Protection Agency Collaborating Laboratory, University Hospital Aintree, Liverpool L9 7AL, UK
  4. 4Abacus Centres for Contraception and Reproductive Health, Liverpool L2 5SF, UK
  1. Correspondence to:
 Sara Jayne Lavelle
 Chlamydia Screening Office, 1st Floor, Muskers Building, 1 Stanley Street, Liverpool L1 6AA, UK; sara.lavelle{at}


Objectives: To identify the prevalence of Neisseria gonorrhoeae (NG) within a population screened for Chlamydia trachomatis (CT). To monitor confirmatory microscopy, culture, and partner findings following reactive Aptima Combo2 assay (AC2) gonorrhoea screening tests.

Methods: Between June and December 2004, all gonorrhoea screening tests performed using AC2 for clients taking part in the Liverpool Chlamydia Screening Programme were monitored. Clients with AC2 NG reactive results were referred to a local genitourinary medicine (GUM) department for confirmatory microscopy, culture, treatment, and partner follow up.

Results: 47 (1%) of 4680 women and eight (1.7%) of 473 men had AC2 reactive gonorrhoea screening tests. Of those clients who agreed to follow up and were tested before any treatment, supportive evidence for a gonorrhoea diagnosis was found in 37 (97%) of 38 women and all five men. In the population opportunistically screened for chlamydia, CT prevalence rates were 12% for women and 15.7% for men. Although both women and men showed a higher relative risk for NG if chlamydia positive, of the 47 women who were reactive for NG by AC2, 55% (26) were negative for chlamydia.

Conclusions: Sexually transmitted infections are rising in England and reduction of gonorrhoea rates is an objective of the Department of Health Sexual Health and HIV Strategy. AC2 tests provide an acceptable and accurate means of testing for gonorrhoea in an asymptomatic population in the community. AC2 had a higher positive predictive value than might be suggested by previous clinical trials in this low prevalence population. Although antibiotic sensitivity must be monitored, AC2 testing may offer a more acceptable alternative to microscopy and culture for NG in some populations.

  • AC2, Aptima Combo2 assay
  • CSO, chlamydia screening office
  • CT, Chlamydia trachomatis
  • FVU, first void urine
  • GRASP, The Gonococcal Resistance to Antimicrobials Surveillance Programme
  • GUM, genitourinary medicine
  • LSSCSP, Liverpool and South Sefton Chlamydia Screening Programme
  • NAAT, nucleic acid amplification test
  • NCSP, National Chlamydia Screening Programme
  • NG, Neisseria gonorrhoeae
  • STI, sexually transmitted infections
  • chlamydia
  • gonorrhoea
  • screening

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  • Competing interests: none.

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