Detection of endocervical anti-Chlamydia trachomatis immunoglobulin A in pregnant women by a rapid, 6-minute enzyme-linked immunosorbent assay: comparison with PCR and chlamydial antigen detection methods

J Clin Microbiol. 1997 Jul;35(7):1781-3. doi: 10.1128/jcm.35.7.1781-1783.1997.

Abstract

There is a need for a rapid, uncomplicated, and inexpensive test for Chlamydia trachomatis infection in women. We evaluated the ability of a 6-min enzyme-linked immunosorbent assay (ELISA) that requires no laboratory equipment (IgA Rapid SeroTest; Savyon Diagnostics) to detect C. trachomatis immunoglobulin A (IgA) in the endocervices of 167 inner-city pregnant women and compared the results with DNA amplification (Amplicor PCR; Roche Diagnostics) and antigen detection (Chlamydiazyme; Abbott Laboratories) performed on the same women. Anti-C. trachomatis IgA was detected in the cervices of 32 women (19.2%). Samples from 23 women (13.8%) were PCR positive, while chlamydial antigen was present in 20 women (12.0%). There was only 1 sample (4.3%) that was positive by PCR but negative by ELISA; 10 samples were ELISA positive and PCR negative. In contrast, seven samples (30.4%) were PCR positive but Chlamydiazyme negative and four were Chlamydiazyme positive and PCR negative. Compared to PCR, the IgA ELISA had a sensitivity of 95.7%, a specificity of 93.1%, a positive predictive value of 68.8%, and a negative predictive value of 99.3%. The antigen assay had a sensitivity of only 69.6%, a specificity of 97.2%, a positive predictive value of 80.0%, and a negative predictive value of 95.2%. In high-risk groups where laboratory testing is not available, or where the patient might not return to obtain her testing result and be treated, the Rapid IgA SeroTest is a viable alternative for detection of cervical C. trachomatis in pregnant women.

MeSH terms

  • Antibodies, Bacterial / analysis
  • Antibodies, Bacterial / immunology*
  • Antigens, Bacterial / analysis*
  • Cervix Uteri / immunology
  • Cervix Uteri / microbiology
  • Chlamydia Infections / diagnosis*
  • Chlamydia Infections / immunology
  • Chlamydia trachomatis / immunology
  • Chlamydia trachomatis / isolation & purification*
  • Enzyme-Linked Immunosorbent Assay / methods*
  • Female
  • Humans
  • Immunoglobulin A / immunology*
  • Polymerase Chain Reaction / methods
  • Pregnancy
  • Pregnancy Complications, Infectious / diagnosis
  • Pregnancy Complications, Infectious / immunology
  • Pregnancy Complications, Infectious / microbiology*

Substances

  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Immunoglobulin A