Endometriosis is a common condition, but getting a correct diagnosis can be a difficult, years-long journey. Now a group of Australian researchers have taken a step towards a breakthrough blood test for the disease, which could be the non-invasive solution so many have been hoping for. 

Endometriosis affects roughly 10 percent of reproductive-age females around the world – that’s about 190 million people, according to the World Health Organization. In people with the condition, tissue similar to the lining of the womb grows in other parts of the body. 

During a normal menstrual cycle, the endometrial tissue on the inside of the womb thickens in preparation for the fertilization and implantation of an egg. If no pregnancy occurs, this lining is shed during a menstrual period. In people with endometriosis, as well as this tissue growth inside the womb each month, similar tissue can grow around other bodily organs. 

Often, the lining of the pelvis (peritoneum) and nearby organs like the ovaries, bowel, and bladder are affected; it’s also possible to find endometriosis in more distant locations like inside the chest, and cases of umbilical endometriosis have even been reported in the literature. 

Some patients are affected from the time of their first menstrual cycle right up until the menopause, which for most people would be a period of several decades. The symptoms can have a significant impact on quality of life, and include severe pain, heavy periods, bowel and bladder issues, fatigue, and difficulty getting pregnant.

But despite how debilitating it can be, and how common it is, patients with suspected endometriosis can wait years for a diagnosis. 

“Currently, [in Australia] it takes on average seven years for a woman to receive a diagnosis and during that time she is enduring significant life impacting symptoms, her years of fertility are reducing and the endometriosis is spreading,” said Professor Peter Rogers, senior author of the new study, in a statement. 

One issue is that it can be hard to definitively detect the condition. The mainstay of diagnosis at present is laparoscopic surgery. A camera is inserted into the abdomen through a small incision, to give clinicians a clearer view of any abnormal tissue that may be growing there. During these procedures, the endometriosis tissue may also be removed – this can successfully put patients into remission, but things can be trickier if the tissue is attached to organs like the bowel, often requiring more complex surgery. 

Although a large percentage of people undergoing surgery may experience good results, endometriosis is not considered to be “curable”. 

Ideally, there would be a way of identifying the condition much earlier, and in a noninvasive way. The team behind the new study are taking steps towards developing a blood test that could help achieve this goal.

“The blood test, called PromarkerEndo, could significantly reduce the cost and the amount of time typically spent on trying to solve the cause of symptoms suffered by women and girls over years, often from as early as when they start having periods,” said co-author Dr Richard Lipscombe.

The test relies on a signature of 10 proteins that can indicate the presence of endometriosis. They’re all proteins that play some role in the disease, such as in the immune response or blood clotting. The study found that the test was reliable at distinguishing between healthy people and those with confirmed, symptomatic endometriosis, even at an early stage of disease. 

“A blood test is more cost-effective for patients and the health system than the current use of ultrasounds, invasive laparoscopies, MRIs and biopsies to diagnose endometriosis, and work is underway to fortify the robustness and reliability of the new test for clinical use,” added Dr Lipscombe. 

With some further testing and development, the authors hope their study has brought us a step closer to a much-needed new diagnostic tool for a condition that, like others affecting the female reproductive system, many would argue has not always got the attention it deserves. 

The study is published in the journal Human Reproduction.