A fortuitous discovery led the inventor of ENDIMETRIX to observe that a combination of certain pigments gives a blue color when upon contact with saliva from a healthy woman with no endometriosis, but no parallel process occurs in assays from women with endometriosis. Continous research and development based on this exciting observation suggested a rapid, non-invasive diagnostic for endometriosis could be developed as a simple color-indicator test of saliva samples. Indeed, the ability of the basic color-change assay to distinguish women with and without endometriosis has been repeatable, and tests on women who provided samples in the follicular phase, yielded an endometriosis test with 92% specificity.