Endometriosis: identification by carbonic anhydrase autoantibodies and clinical features

Reliably diagnosing endometriosis traditionally requires surgery. To evaluate a possible non-surgical method, a case-control series of unexplained infertility patients undergoing diagnostic laparoscopy were scored by clinical criteria and reactivity to human carbonic anhydrase II by Western blotting. The CA II autoantibodies were found in none of the fertile controls, 38 percent of infertile controls, 55 percent of stage 1, 50 percent of stage 2, 73 percent of stage 3, and 85 percent of stage 4 endometriosis patients. Advanced endometriosis was associated with more intense reactivity. Combining clinical and antibody scores for infertile groups showed a positive association with disease stage with positive predictive values of 76 to 95 percent, negative predictive values of 90 to 60 percent, and a likelihood ratio of 18.3. It is concluded by us that CA II immunoreactivity, clinical, and combined scores all identified stages 2 to 4 endometriosis patients. However, based on predictive values and likelihood ratios, the combined score is best at identifying endometriosis non-surgically.