Chlamydia trachomatis antibody testing is more accurate than hysterosalpingography in predicting tubal factor infertility.

Objective: To compare the likelihood of abnormal Chlamydia trachomatis antibody test results with that of abnormal hysterosalpingography (HSG) test results in patients with tubal factor infertility.

Design: Anti-C. trachomatis immunoglobulin G antibodies were determined prospectively in 211 consecutive infertility patients by means of an indirect fluorescent antibody technique. The results were compared with the results of HSG with respect to their predictive value of tubal factor infertility. Likelihood ratio calculations were used.

Setting: University hospital-based, tertiary care infertility clinic.

Patients: A series of 211 consecutive infertility patients.

Interventions: C. trachomatis antibody testing, HSG, laparoscopy.

Main Outcome Measures: Likelihood ratios for abnormal C. trachomatis antibody test results and abnormal HSG results in infertility patients, as assessed by laparoscopy.

Results: The positive likelihood ratio for C. trachomatis antibody testing was 9.1, indicating a patient with tubal factor infertility to be 9.1 times more likely to have abnormal serology results than a patient without tubal factor infertility. This was superior to HSG, which had a positive likelihood ratio of 2.6 in our study and of 1.6 to 6.1 in the literature. The odds ratio of C. trachomatis antibody testing was 31.5 in our study. Its 90% confidence interval (8.3 to 138.5) did not overlap that of HSG as calculated from a meta-analysis of literature reports (5.3 to 7.9).

Conclusions: C. trachomatis antibody testing is simple, inexpensive, and causes minimal inconvenience to the patient. It is more likely than HSG to be abnormal in patients with tubal factor infertility. C. trachomatis antibody testing deserves to become an integral component of the initial fertility work-up.