CYFRA 21-1 in urine: a diagnostic marker for endometriosis?

Diagnostic workup of endometriosis usually involves laparoscopic inspection and histological examination of biopsies. Unequivocal laboratory parameters for this ailment have not been available in routine diagnostic evaluations thus far. In this study, we examined urine concentrations of cytokeratin 19 (CYFRA 21-1), a structural protein specific for epithelia. We performed immunoassays for CYFRA 21-1 in urine samples from women afflicted with endometriosis throughout their menstrual cycle. We observed a significant increase in CYFRA 21-1 concentrations, corrected by creatinine levels, in the late follicular phase as compared with the level in healthy controls. We conclude that cyclically increased CYFRA 21-1 concentrations in urine could serve as a valuable noninvasive diagnostic parameter in the workup of clinically manifesting endometriosis.