Screening for Chlamydia – can we do better without any extra
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.