RESUMO
OBJECTIVE: To determine whether routine testing for serum Chlamydia trachomatis antibodies, considered in combination with a woman's clinical features, may avoid the need for diagnostic laparoscopy in routine investigation for infertility. DESIGN: Retrospective case notes analysis. SETTING: Secondary level care infertility clinic. POPULATION: Eighty women who had undergone both laparoscopy and serum Chlamydia trachomatis antibody testing. METHODS: Ascertainment of any history of suspected pelvic inflammatory disease, pelvic pain, cervical intraepithelial neoplasia, pelvic surgery or appendicectomy; any abnormality on clinical pelvic examination; the findings at laparoscopy; the result of serum Chlamydia trachomatis antibody testing by enzyme-linked immunosorbent assay (ELISA) screening with microimmunofluorescence (MIF) confirmatory diagnostic testing. The usefulness of clinical features, the serum Chlamydia trachomatis antibody test and these two variables combined in the detection of tubal disease and pelvic pathology of relevance to infertility were measured statistically. MAIN OUTCOME MEASURES: Specificity, sensitivity, positive predictive value, negative predictive value and likelihood ratio for each of the tests. RESULTS: The combination of any positive clinical feature with a positive test for serum Chlamydia trachomatis antibodies detects tubal disease with sensitivity 92%, specificity 70%, positive predictive value 72%, negative predictive value 91% and likelihood ratio 3 x 1; it detects bilateral tubal obstruction with sensitivity 84%, specificity 51%, positive predictive value 35%, negative predictive value 91% and likelihood ratio 1 x 7; it detects pelvic pathology relevant to infertility with sensitivity 76%, specificity 71%, positive predictive value 80%, negative predictive value 65% and likelihood ratio 2 x 6. The negative predictive value for pelvic pathology from the use of clinical features in addition to the chlamydia antibody test is not significantly higher than that from the chlamydia antibody test alone (53%). CONCLUSIONS: A policy of selective laparoscopy in routine investigation for infertility, based on the result of the test for serum Chlamydia trachomatis antibodies and a woman's clinical features, is not supported.