Endometriosis affects an estimated 10% of reproductive-age women worldwide. Early diagnosis is crucial for preventing disease progression, improving pain management, and preserving fertility, yet long delays are common. In fact, a recent survey by the nonprofit Endometriosis UK reported an increase in the average diagnosis wait time to nine years and four months in the UK for 2025.
Endometriosis is a chronic oestrogen-dependent inflammatory condition characterised by growth of endometrial-like tissue, or lesions, outside the uterine lining. It is classified broadly into four stages, with superficial peritoneal endometriosis being the earliest stage and most common form, but also the most difficult to diagnose.
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A laparoscopy is still needed for a conclusive diagnosis, but the non-invasive diagnostic research space has gained momentum in recent years with several innovative tests in late-stage development. A 2025 GlobalData report predicts that overall market sales will reach $2.5 billion in 2034, with improved diagnosis rates due to non-invasive tests expected to be a major driver of growth. GlobalData is the parent company of Pharmaceutical Technology.
Nonetheless, despite interest from private companies, there has not been adequate funding from the National Institutes of Health (NIH) to move the needle, says Dr. Hugh Taylor, Anita O’Keeffe Young professor of Obstetrics, Gynaecology, and Reproductive Sciences at Yale School of Medicine. Farideh Bischoff, PhD, CMO of Burlington, Massachusetts-based HerAnova, a biotech developing a blood-based endometriosis test, says she has observed industry focus shifting from therapeutics to diagnostics in the last 12 months, adding that investors are beginning to see the value in women’s health. While biotechs around the globe are touting high levels of test accuracy and specificity, several key challenges lie ahead, including incorporation in clinical guidelines and ensuring access for patients.
Why are diagnosis rates so slow?
The cause of extensive delays to diagnosis of endometriosis is a culmination of multiple factors, says Taylor. A lack of awareness and misconceptions around the disease among patients and even healthcare professionals can lead to normalisation of symptoms, he explains.
Also, endometriosis-related pain is difficult to quantify, highlights Taylor. This sentiment is echoed by David Hail, CEO of Serac Healthcare, a London, UK-based biotech developing a radioligand tracer for endometriosis diagnosis. Hail says patients often use family members as a reference point for period pain, which is complicated due to the hereditary component of the disease.
Furthermore, misdiagnosis is common. For example, if the intestines become irritated because of endometriosis, patients are often referred to a gastroenterologist for a bowel disease evaluation, explains Taylor.
Laparoscopy is considered the gold standard for diagnosis, but since it requires surgical intervention, it is often avoided until symptoms become severe, says Taylor, who has been advocating for inclusion of a recommendation for clinical diagnosis in guidelines for years. Updated February 2026 American College of Obstetricians and Gynaecologists (ACOG) guidelines strongly advise initiation of empiric treatment from a clinical diagnosis based on symptoms and/or physical examination.
There are several approaches being explored for non-invasive diagnosis of endometriosis. Serac is investigating an imaging agent, the radiolabelled tracer 99mTc-maraciclatide, to diagnose endometriosis. Maraciclatide binds to αvβ3 integrin, which is upregulated in angiogenesis, a key hallmark of inflammation, including in superficial peritoneal endometriosis. Early findings from an observational study named DETECT (NCT05623332) have shown maraciclatide can detect this early form of endometriosis, which cannot be reliably imaged with ultrasound and magnetic resonance imaging (MRI). Full study results are due to be published within the next few weeks, says Hail. Maraciclatide has an FDA fast track designation, and the FDA has agreed upon Serac’s outline design for Phase III trials for regulatory approval, says Hail.
Lyon, France-based Ziwig has opted for a microRNA-based approach. Its researchers identified an endometriosis signature composed of 109 microRNA, which its diagnostic product Endotest matches with saliva samples. In a prospective multicentre validation study, the test reported 96.6% accuracy and 94.1% specificity of the microRNA signature in a population of 971 patients.
The at-home test received a CE mark in March 2022, and is currently available in Europe, including in the UK at a price of approximately GBP800 ($1,056), and the Middle East. In France, Endotest is being made available to 25,000 women in an early access program across 100 hospitals, generating real-world data on clinical utility and quality of life, says Andrew Spiers, clinical lead at Ziwig. A key advantage for using saliva is its stability; it is stable at room temperature for 30 days, which may enable access in resource-limited settings, says Spiers. The microRNA diagnostic approach is good, and while expensive, the hope is that the price will reduce as the technology moves forward, says Taylor.
Other approaches being investigated include a protein-based blood test developed by Proteomics International called PromarkerEndo, which provides a risk score for endometriosis based on a panel of 10 protein biomarkers. The company recently presented external validation data at the 16th World Congress on Endometriosis in Australia from 436 endometriosis cases, where the test indicated 83% sensitivity and 95% specificity. PromarkerEndo is due to be launched first in Australia and then the US, says Catherine Wingate, product manager, Proteomics International.
Meanwhile, HerAnova has taken a multi-omics approach for its CLIA-validated HerResolve blood-based assay. The test leverages artificial intelligence (AI) to analyse data for three microRNAs, three protein biomarkers, one steroid hormone, as well as the participant’s age and body mass index, to give a diagnosis. A recently published multicentre case-control study indicated 94.4% accuracy and 97.5% specificity when tested in 298 women. The company has filed for a New York State Clinical Laboratory Evaluation Program, with plans to submit to the FDA in Q3 2026, says Bischoff. The test is being rolled out in fertility centres in the US, with Bischoff saying that real-world data can support reimbursement discussions with payers.
Road to implementation
Once approved, getting reimbursed access to these tests remains a challenge. Generating evidence of improved quality of life and cost-effectiveness will be key to ensuring reimbursement coverage, says Hail. Meanwhile, Taylor says that studies comparing the effectiveness of diagnostics to laparoscopy, along with favourable pricing, may be sufficient for widespread uptake.
Novel diagnostic approaches also need to be integrated with clinical guidelines. The recently updated ACOG guidelines strongly recommend against using blood, urine, or endometrial biomarkers, stating that none have yet demonstrated sufficient accuracy for use in clinical practice. Spiers recognises inclusion in guidelines as an important step, noting that he hopes the company’s recent publications support a paradigm shift away from traditional diagnostic techniques.
The wider R&D landscape for endometriosis
Despite advancements in diagnostics, treatment options for endometriosis remain limited. Currently, clinical trials for disease-modifying drugs are likely to depend on baseline and follow-up laparoscopic surgery to assess therapeutic effect, leading to recruitment challenges, says Hail. As a result, studies tend to recruit patients with severe disease, and therefore results may not be representative of the superficial peritoneal endometriosis population, adds Taylor.
Pain can also be utilised as an endpoint, but it is not an objective measure, says Hail. In addition, pain may not accurately reflect active endometriosis due to scarring-associated pain, and it correlates poorly with lesion size and stage, he adds.
Availability of an alternative validated diagnostic would be foundational for development of new therapeutics, says Hail. Serac is in discussion with several large pharma companies regarding use of maraciclatide in clinical studies for endometriosis therapeutics as a potential route to approval.
In the future, biomarkers may be leveraged as predictive tools to guide personalised treatment, says Taylor. He and other researchers at Yale School of Medicine recently identified a DNA-methylation signature in circulating leukocytes that can predict progestin responsiveness in endometriosis and thereby may help avoid inappropriate treatment.
Ultimately, endometriosis will likely require a precision-medicine approach due to its complexity, says Bischoff, explaining that different subpopulations may have distinct underlying disease mechanisms.
