Chlamydia trachomatis antigen detection in pregnancy and its verification by antibody blocking assay.

PURPOSE To detect the prevalence of genital infection caused by Chlamydia trachomatis in pregnant women and also to confirm the positive results using blocking antibody assay. METHODS Endocervical specimens were collected from 200 symptomatic and asymptomatic pregnant women attending the ANC OPD at M P Shah Medical College, Jamnagar. The samples were tested for presence of Chlamydia trachomatis antigen using the monoclonal antibody. Blocking antibody assay was used to further verify the positive results. RESULTS Out of 200 pregnant women, 38 (19%) were found positive for Chlamydia trachomatis antigen. Out of the 68 symptomatic patients, C. trachomatis antigen was detected in 26.4%. After verification of the positive samples 13.6% of the asymptomatic pregnant women were found to be harbouring the infection in their genital tract. Two (5.2%) out of the 38 positive samples, on verification with the blocking antibody assay, were found to be false positive by IDEIA,TM thus the specificity of the IDEIATM being 94.8%. In patients with previous history of abortions, 27.7% were tested positive for C. trachomatis infection. CONCLUSIONS Significant number of pregnant women shad C. trachomatis antigen in their endocervical canal, which can be easily diagnosed by this simple enzyme immuno assay having a specificity of 94.8%. Verification of positive results by antibody blocking assay can further improve the specificity of this non-culture test. Asymptomatic patients should also be screened for the infection. History of previous abortions places the patient at a higher risk for C. trachomatis infection thus such patients should be definitely tested for chlamydia infection.