Diagnosis method of endometriosis by detecting biochemical markers and usage of these biochemical markers

The present invention relates to a non-invasive diagnosis method of endometriosis by detecting biochemical marker in serum or peritoneal fluid, in particular alpha 1-antitrypsin, fragments of alpha 1-antitrypsin, or a combination of both. The diagnosis of endometriosis is performed with observing in serum specimens of a patient the concentration and change of the biochemical marker, in particular molecules related to alpha 1-antitrypsin, and comparing with a predetermined baseline level of the biochemical marker contained in serum. Statistical analysis can be performed to evaluate the baseline level indicating the occurrence of endometriosis. Therefore, the present invention can provide an auxiliary guideline for the diagnosis of endometriosis. The present invention also relates to usage of the biochemical marker.