Chlamydia Rapid Test and False Negatives
Sensitivity and specificity of the Chlamydia Rapid Test using vaginal
swab specimens in comparison to polymerase reaction assay or strand
displacement amplification assay are high (> 80%) (1). The results are
available within 30 minutes versus one to two weeks for nucleic acid
amplification tests. Nevertheless, currently the Chlamydia Rapid Test
cannot totally replace the PCR.
Indeed, a recent study compared the sensitivity and specificity of
the Chlamydia Rapid Test with the PCR (2). The study involved 1484 female
sex workers attending a social hygiene clinic and 838 women attending an
obstetrics-gynaecology clinic. In the high-risk population (female sex
workers), 29% of women (1/4) infected by the chlamydia trachomatis had a
negative Chlamydia Rapid Test (sensitivity 71%) compared with PCR. In low
risk-population 13% of women (1/7) infected by the chlamydia had a
negative Chlamydia Rapid Test (sensitivity 87%).
In case of the discordance between the clinical symptoms and
Chlamydia Rapid Test or in a high-risk population, the Chlamydia Rapid
Test is insufficient and the PCR remains the gold standard.
Finally, the medical cost of a widespread screening by Clamydia Rapid
Test should be evaluated in relation to its medical benefit.
1. Mahilum-Tapay L, Laitila V, Wawrzyniak JJ, Alexander S, Swain A,
Barber P,Ushiro-Lumb I, Goh BT, Ison C, Lee HH. New point of care
Chlamydia Rapid Test bridging the gap between diagnosis and treatment:
performance evaluation study. BMJ 2007;335:1190-1194
2. Saison F, Mahilum-Tapay L, Michel CE, Buttress ND, Nadala EC Jr,
Magbanua JP, Harding-Esch EM, Villaruel MO, Canong L, Celis RL, Lee HH.
Prevalence of Chlamydia trachomatis Infection among Low- and High-Risk
Filipino Women and Performance of Chlamydia Rapid Tests in Resource-
Limited Settings. J Clin Microbiol. 2007;45:4011-7.
Competing interests: No competing interests