A new saliva test for endometriosis is in trials. What this and other new endo tests mean for you

Endometriosis is a condition where tissue resembling the lining of the uterus is found outside the uterus, causing severe period and pelvic pain, pain during intercourse, bowel and bladder issues, and fertility challenges. Currently, diagnosis involves symptom assessment, physical examination, imaging, and sometimes surgery. However, these methods can be lengthy and uncertain, leading to years of pain, repeated appointments, and delayed treatment for patients.

Two new non-invasive tests for endometriosis are currently being trialled in the United Kingdom. One is a saliva test called Endotest, which analyzes a saliva sample for specific markers called microRNAs. A French study found this test to be highly accurate, but most participants had endometriosis, raising questions about its performance in the typical mix of patients seen in general practice.

Another test, EndoSure, measures electrical signals in the gut via sensor pads on the abdomen. A study reported 95% sensitivity (ability to correctly detect endometriosis) and 96% specificity (ability to correctly rule out people who do not have endometriosis), but the specificity figure's reliability is questionable due to the lack of surgical confirmation in the control group.

Australia has its own non-invasive test, PromarkerEndo, which measures proteins in blood. This test has been shown to have promising results in patients with symptoms but where surgery has found no endometriosis. Another blood-based test, DotEndo, examines microRNAs in blood and is currently in development. However, results from a large, multi-centre study are needed to fully assess its usefulness. Other non-invasive tests for endometriosis are also in development, including blood tests and other blood-based tests.