Screening for Chlamydia - can we do better without any extra funding?

S. Uthayakumar, P. Thayaparan, F. Paruk, A. Agrawal

Department of Sexual Health, Woodlands clinic, Lister Hospital, Stevenage, Hertfordshire, UK

Introduction Opportunistic testing for Chlamydia trachomatis has been recommended to reduce long-term morbidity in women, especially at Family Planning clinics. At present majority of the laboratories use Enzyme Immuno Assay (EIA), which has a sensitivity of 60-70% and specificity of >99%. EIA is cheaper compared to nucleic acid amplification tests (NAAT). The sensitivity of an EIA test could be increased by carrying out dual sampling of Chlamydia from the urethra and cervix and inoculated in the same tube but the cost would be the same as a single swab. However, the pain when taking a urethral swab might be a disadvantage. This study is aimed to compare the results of the Chlamydia EIA test by dual sampling as opposed to cervical sample only.

Methodology Consecutive new female attendees to the Sexual Health clinic between Dec. 2004 and May 2005 were enrolled into the study. During this period cervical Chlamydia was tested in 223 women and dual sampling was carried out in 258 women. They also had screening for other sexually transmitted infections. 

Results Epidemiological data and the risk factors between both groups were similar. The prevalence of Chlamydia on a cervical swab alone was 9% and on a cervical and urethral swab was16.6%. Dual sampling significantly increases the diagnosis of Chlamydia (p <0.001).

Discussion and conclusion For most FP clinics, obtaining additional funding for NAAT screening test for Chlamydia is an impossible task. The discomfort when taking urethral swab was tolerable by over 95% of the women. This study showed, when Chlamydia screening is carried out in women using and EIA test, dual sampling would be beneficial as it increases the sensitivity of the tests at no extra cost.