Laboratory testing for endometriosis

BACKGROUND: Typically, endometriosis is diagnosed surgically by laparoscopy. CA-125 is the principal serum marker used in the diagnosis and management of late-stage endometriosis. The search for a body fluid marker of early stage disease has included studies of serum, peritoneal fluid (PF), and/or tissue levels of secretory proteins, cell adhesion molecules, cytokines, tumor necrosis and vascular endothelial growth factors (VEGFs), chemokines, antiendometrial antibodies, autoantibodies to oxidized lipoproteins, aromatase P-450 expression, cytokeratins, and hormone receptors. We compared the diagnostic accuracy and clinical utility of these various types of substances in the non-surgical identification of patients with endometriosis. METHOD: We reviewed the MEDLINE database for all publications on serum, peritoneal fluid and tissue markers of endometriosis. RESULTS: Except for serum interleukin (IL)-6 and peritoneal fluid tumor necrosis factor (TNF)-alpha levels, the diagnostic accuracy of other markers of endometriosis was either similar or worse than that of CA-125 (sensitivity 24-94%; specificity 83-93%). The diagnostic accuracy of IL-6 and TNF-alpha was 90-100% (sensitivity) and 67-89% (specificity). CONCLUSION: CA-125 has limited diagnostic accuracy in the identification of early stage endometriosis and none of the other markers we reviewed dramatically outperformed CA-125 in this regard with the possible exception of serum IL-6 and peritoneal fluid TNF-alpha levels.