One in 10 women have endometriosis, but diagnosis usually takes eight years. A simple spit test could soon help women find out for themselves if they have the condition.
Endometriosis is caused by uterus cells moving elsewhere in the body and bleeding in time with a woman’s menstrual cycle. It affects 176 million women worldwide and can cause severe pain as well as infertility. The longer it takes to diagnose the condition, the more scarring takes place.
“It’s inexcusable that, for many women, those are lost years of excruciating pain, or not knowing why they’re not able to get pregnant,” says Heather Bowerman, a bioengineer and CEO of , in San Francisco.
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Part of the problem is that doctors don’t always realise when a woman’s menstrual pains are worse than what is normally expected for a period. But diagnosis is also delayed by the fact that the condition can only be conclusively diagnosed by surgery.
“The main thing that is so frustrating is the time to get a diagnosis,” says Kaye Sedgwick-Jones, who lives in Kent, UK, and has experienced endometriosis symptoms for 22 years, since the age of 14. “Anything to bring that down, so other women don’t have to go through what I went through, is a positive step.”
Towards a test
Two diagnostic tests, made by DotLab, might change that. Both are designed to detect small pieces of genetic material, called microRNAs, that differ in concentration in the body fluids of women who have endometriosis compared with those who don’t have the condition.
Hugh Taylor at the Yale School of Medicine has found that two specific microRNAs in the blood can be used to predict whether a woman has endometriosis with around 90 per cent accuracy. The technique is now being tested on 100 women who don’t yet know the cause of their pelvic pain, but who are undergoing surgery to find out. The results of their surgeries will then be compared with the predictions from the blood test.
The team will present its findings from the more than 80 women who have undergone surgery so far at the American Society for Reproductive Medicine conference in Houston, Texas, this month, and are seeking regulatory approval for this blood test in the US.
, at the University of Oxford, is cautious, saying the blood test results will need to be replicated in other groups of women before the method is developed into a test to be used for diagnosis. “We need to see that these signals are robust in different populations before we start advising women to start buying tests.”
However, the team has also developed a diagnostic test based on microRNAs in saliva, instead of blood. They haven’t yet published any data from their ongoing assessment of the test, but plan to start taking orders for test kits soon. There are fewer regulatory hurdles for spit testing kits, and doctors in the US will be able to place orders by the end of October. Within six months, women in the US may be able to order them for themselves.
Earlier treatment
“If this were to hold up it would be amazing,” says Zondervan. “Finding a biomarker that would actually prioritise women to be screened for endometriosis at a much earlier stage after they develop symptoms is the holy grail, that’s what we’re all aiming for.”
But Zondervan warns that the team’s findings may not translate easily to saliva, and further tests would be needed to show this second diagnostic really works.
“It’s in really early stages and there needs to be an awful lot more work done to make sure it really does pick up endometriosis,” says Emma Cox at the charity . She says that much more research is needed to know the test is accurate enough to be used by women of different ages and ethnicities, for instance.
If the tests do hold up, they could help women improve diagnosis and treatment. “If we could have a test that says what this pain is earlier, then I think we could get people therapy earlier,” says Taylor.
Oral contraceptives are usually tried as an initial therapy for endometriosis, as these can make menstrual bleeding less severe or stop women from having periods. But this doesn’t work for everyone, and some women are prescribed other hormone-blocking drugs.
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