Saliva test for endometriosis. A breakthrough in diagnostics or a market curiosity?

Before we dive into this topic, a quick and important reminder: The content shared on the EndoMe blog is for educational and informational purposes only. It does not replace consultation with a specialist and should not be used as a basis for making medical decisions on your own.

Every so often, a piece of news appears on social media that literally electrifies women struggling with endometriosis. A non-invasive diagnostic test, results obtained from a simple saliva sample, and the promise of an end to the years-long agony of waiting for a correct diagnosis. Such posts quickly garner thousands of shares, and comment sections are flooded with questions about availability, price, and effectiveness. This overwhelming enthusiasm is entirely understandable, as the problem this test is supposed to solve affects millions of women worldwide and drastically disrupts their daily lives. However, before we succumb to this justified hope, it's worth taking a hard look at the scientific facts, understanding the mechanism of this method, and discovering why the path from laboratory discovery to the gynecologist's office can be so tortuous.

Why does endometriosis diagnosis still take so long?

To fully understand why the topic of non-invasive testing evokes such extreme emotions, we must first consider the realities faced by patients. The average time from the first painful symptoms to a final diagnosis currently ranges from seven to even ten years. During this time, women shuttle between specialists' offices, often being told that their beauty, period pain, or the problem is purely psychological. During this time, the disease continues to progress, destroying internal organs and perpetuating changes in the body, drastically reducing quality of life.

The main reason for this diagnostic paralysis is that for decades, the only 100% reliable method for confirming endometriosis was laparoscopy combined with histopathological examination of the collected biopsy specimen. This is a major surgical procedure that requires general anesthesia, a hospital stay, and the presence of a highly specialized surgeon. For obvious reasons, this procedure is not routinely performed on every adolescent or adult woman reporting severe abdominal pain.

Of course, modern high-resolution transvaginal ultrasound and pelvic magnetic resonance imaging (MRI) now allow for the detection of many advanced forms of the disease, especially endometrial cysts and deeply infiltrating lesions. Unfortunately, superficial and subtle peritoneal lesions can remain completely invisible even with the best equipment. This is why finding a simple, non-invasive marker in body fluids has become the holy grail of modern gynecology.

What is microRNA and why has it attracted the interest of researchers?

In their search for the perfect indicator, scientists have turned their attention to microRNAs. These are short, non-coding ribonucleic acid molecules that act as controllers in our bodies. Although they don't produce proteins themselves, they determine which genes in a given cell are activated and which are silenced. The human body produces hundreds of different microRNA molecules, and their relative proportions and activity profiles change depending on whether we are healthy or whether inflammation or disease is developing.

Researchers have discovered that in women with endometriosis, the distribution of these molecules in body fluids, including blood and saliva, is completely different than in healthy patients. This discovery immediately raised the question of whether analysis of these specific profiles could serve as a safe and painless diagnostic marker. Saliva seems to be an ideal material in this regard, as its collection is painless, requires no medical personnel or needles, and the patient can collect the sample themselves at home. If such a test were to achieve sufficient accuracy, it could become a brilliant screening tool, quickly directing at-risk women to specialized centers.

What stage of research are we actually at?

It's important to be particularly precise here, as a vast gulf stretches between promising headlines and actual clinical practice. The studies published to date on the use of salivary microRNA are still largely preliminary, conducted on relatively small, carefully selected patient groups. Although some publications report impressive test sensitivity and specificity exceeding 80 percent, the reality presents significant challenges.

First and foremost, these studies were conducted in near-ideal laboratory conditions. Translating these results to the general population of women with co-occurring inflammatory conditions, infections, or hormonal imbalances can be extremely difficult. Endometriosis is an extremely heterogeneous disease, manifesting itself in various ways, and it remains uncertain whether the microRNA profile changes identically in small peritoneal lesions as in advanced, deep forms.

Moreover, various research centers around the world continue to debate which specific microRNA molecules are most reliable, preventing full standardization of the method. Crucially, this technology has not yet undergone the rigorous clinical validation required by key global regulatory agencies, such as the European Medicines Agency or the US FDA.

Commercial tests on the market and the reality of patients

Despite these question marks, the first tests based on this technology have already appeared on the commercial market, offered for a fee to private patients in some European countries and Australia. The situation in which a product is released for sale before the final conclusion of global clinical trials is causing considerable controversy in the scientific community. Enormous market pressure and the desperation of women seeking answers mean that business sometimes outpaces official medical recommendations.

Releasing an insufficiently validated test to the market carries real risks. A false negative result can lull a woman into a false sense of security and delay appropriate surgical or pharmacological treatment. A false positive result, on the other hand, generates significant stress and can lead to unnecessary, invasive medical procedures. If you're considering private testing, it's crucial to consult with your doctor, who can reliably assess the reliability of the method in your specific case.

Why do history and imaging still win out?

Even in the most optimistic scenario, in which the saliva test successfully passes all verification stages and becomes part of the official medical canon, it will not replace traditional diagnostics, but merely alter its current path. Such a test would ideally serve as a first screening test. A positive result would not be a final decision, but a clear signal to the gynecologist that the patient should urgently be referred for advanced imaging and receive special care.

No biomarker, even the most advanced, can replace what an experienced physician can determine during a thorough consultation in the office. A detailed clinical interview, analysis of the nature of the pain, its precise location, correlation with the menstrual cycle, and accompanying symptoms in the digestive and urinary systems, combined with precise palpation and ultrasound, will remain the foundation. Endometriosis is a complex disease affecting the entire body, and a complete understanding of it will always require a person with a comprehensive clinical picture of the patient.

Future prospects

The very fact that research on microRNA and saliva tests is developing so rapidly is fantastic news. It demonstrates that the problem of dramatic diagnostic delays in endometriosis is no longer taboo and is being treated with due priority by science. Realistically, we will have to wait a few to a dozen years for the full implementation of repeatable, universally recognized, and reimbursed screening tests. Until then, it's worth following all news with a healthy, rational critical eye, remembering that when it comes to health care, haste and media revelations are rarely good advisors.

Źródła:

• Bendifallah S. et al. Salivary microRNA as a diagnostic tool for endometriosis: a systematic review. Journal of Clinical Medicine, 2022.
• Wei N. et al. Diagnostic value of miRNAs in endometriosis: a systematic review and meta-analysis. BMC Women's Health, 2026.
• Moawad G. et al. High accuracy salivary miRNA signature for non-invasive diagnosis of superficial peritoneal endometriosis: a large prospective multicenter study. Obstetrics & Gynecology, 2026.
• Nisenblat V. et al. Biomarkers for the non-invasive diagnosis of endometriosis. Cochrane Database of Systematic Reviews, 2016.
• Vercellini P. et al. Endometriosis: pathogenesis and treatment. Nature Reviews Endocrinology, 2014.
• ESHRE Endometriosis Guideline Development Group. Endometriosis: guideline of the European Society of Human Reproduction and Embryology. ESHRE, 2022.