The findings of a study demonstrated that the combination of non-invasive markers thyroid-stimulating hormone [TSH] level and premenstrual spotting is valuable for precise non-invasive prediction of endometriosis, thus increasing the accuracy of non-surgical diagnosis. Researchers performed this retrospective, case-control study for determining if combination of a TSH level > 2.5 µlU/ml and premenstrual spotting can be used as common markers of endometriosis.

The researchers also explored if the typical symptoms of endometriosis, such as dysmenorrhea and/or dyspareunia, can raise the diagnostic reliability. The study enrolled 167 female patients (107 with surgically confirmed endometriosis and 60 without endometriosis [control group]). Specificity, sensitivity, and predictive values were taken into consideration for assessing the diagnostic accuracy.

For determining the link between endometriosis and markers, an odds ratio (OR) with a 95% confidence interval [CI] was estimated. Application of both markers (elevated TSH and premenstrual spotting) resulted in an accurate diagnosis of endometriosis in 52% of females. The addition of symptoms such as dyspareunia and dysmenorrhea did not considerably increase the diagnostic accuracy. Endometriosis was accurately classified in 50% of females having thyroid dysfunctioning, dysmenorrhea and premenstrual spotting.

In the case of premenstrual spotting alone, endometriosis was accurately classified in 61% of females. Endometriosis diagnosis via the non-invasive markers as per their sensitivity provided the following ranking: raised levels of TSH, premenstrual spotting, combination of both the prior parameters, addition of dysmenorrhea and dyspareunia, and combination of all the parameters.

Besides an elevated level of TSH, the existence of premenstrual spotting emphasizes the possible diagnosis of endometriosis with the markers. Thus, the history of the patient should be meticulously considered.