Context and objective: One of the diagnostic markers of endometriosis is CA-125, and elevated levels of this are caused by high concentrations in the ectopic endometrium. The objective of this study was to correlate CA-125 levels in serum and peritoneal fluid from women with and without pelvic endometriosis.
Design and setting: This was a prospective, cross-sectional, controlled study of consecutive patients undergoing laparoscopy for infertility, pelvic pain or tubal ligation, during early follicular phase, at the university hospital of Faculdade de Medicina de Ribeirão Preto.
Methods: Fifty-two patients were divided into two groups: endometriosis group, consisting of 35 patients with biopsy-confirmed pelvic endometriosis, and control group, consisting of 17 patients without endometriosis. CA-125 levels in serum samples and peritoneal fluid were determined by chemiluminescence.
Results: CA-125 levels in serum and peritoneal fluid were higher in patients with advanced pelvic endometriosis (means of 39.1 +/- 45.8 U/ml versus 10.5 +/- 5.9 U/ml in serum, p < 0.005; 1,469.4 +/- 1,350.4 U/ml versus 888.7 +/- 784.3 U/ml in peritoneal fluid, p < 0.05), and showed a positive correlation between each other (correlation coefficient (r) = 0.4880). Women with more advanced degrees of endometriosis showed higher CA-125 levels in both serum and peritoneal fluid (p = 0.0001).
Conclusion: There is a positive correlation between serum and peritoneal fluid values of CA-125 in women with and without endometriosis, and their levels are higher in peritoneal fluid. Advanced endometriosis is related to higher levels in both serum and peritoneal fluid.