Non-invasive blood test offers new diagnostic approach for endometriosis

Non-invasive blood test offers new diagnostic approach for endometriosis | Image Credit: © Bartlomiej Zyczynski - stock.adobe.com.

Kephera Diagnostics has announced the introduction of EndomTest, the first commercially available non-invasive diagnostic test for endometriosis in the United States, according to the company.

The laboratory-developed test (LDT), which requires only a blood sample, is designed to serve as a rule-in tool for the disease and may offer a significant advancement in reducing diagnostic delays commonly experienced by patients.

Endometriosis affects approximately 10% of women of reproductive age, or roughly 6.5 million individuals in the United States, and is associated with pelvic pain, infertility, and reduced quality of life. Diagnosis is often delayed, averaging 7 years from symptom onset, due to reliance on laparoscopy and histologic confirmation as the gold standard.

“Endometriosis is a serious medical and gynecological condition affecting many women, of all ages,” said Michael Krychman, MD, of the University of California Irvine Medical Center. “Currently, our only diagnostic approach is laparoscopic surgery, an invasive procedure that carries inherent risks and side effects. A simple non-invasive test for endometriosis has the potential to transform patient care.”

The EndomTest is based on more than a decade of academic research and is offered under exclusive license from Exeltis. It utilizes a combination of serum biomarkers—cancer antigen 125 (CA125) and brain-derived neurotrophic factor (BDNF)—and 6 clinical variables derived from patient history. These include previous surgical history for endometriosis, presence of painful periods leading to referral, severity of menstrual pain, age at first use of painkillers, age at first diagnosis of ovarian cysts, and age at onset of dyspareunia. Results are processed through a diagnostic algorithm to yield a binary outcome: positive or negative.^2,3

Validation of the test was conducted using samples from the Oxford Endometriosis CaRe Centre biobank in the United Kingdom. The development study included 204 patients, and the external validation study included 79 patients. Endometriosis diagnoses in both cohorts were based on laparoscopic and histological confirmation.

In the validation study, the test demonstrated a specificity of 100% (95% CI: 86.7–100%) and a sensitivity of 46.2% (95% CI: 25.5–66.8%), supporting its utility as a rule-in test. The area under the curve (AUC) was 0.758. Importantly, the test showed sensitivity of 32% for superficial endometriosis, which is difficult to detect with imaging, and higher sensitivity in cases of deep infiltrating endometriosis (DIE) and endometrioma, particularly when both lesion types co-occur (sensitivity 69.7%).

Despite the presence of confounding gynecologic conditions such as uterine fibroids, ovarian cysts, and polycystic ovarian syndrome among control participants, the test maintained high specificity. “People are told that their symptoms are normal when they are experiencing disabling pain,” said Caroline Leithner, a patient and advocate. “As a patient who has had a laparoscopy and treatment with 18 months of a GnRH agonist, this test would have offered me the option for less invasive testing and more options for earlier treatment of my disease.”

Andrew Levin, PhD, chief executive and scientific officer at Kephera Diagnostics, stated, “We are proud to be launching the first non-invasive test for endometriosis in the United States. EndomTest leverages Kephera’s scientific expertise in in vitro assays for challenging diseases. With the launch of this test through our CLIA lab, we hope to provide a diagnostic solution that will improve healthcare for thousands of patients who are affected by endometriosis.”

References:

1. Kephera Diagnostics. First Blood Test for Endometriosis Launched by Kephera Diagnostics. Kephera. July 24, 2025. Accessed July 24, 2025. https://kephera.com/first-blood-test-for-endometriosis-launched-by-kephera-diagnostics/
2. Herranz-Blanco B, Daoud E, Viganò P, García-Velasco JA, Colli E. Development and Validation of an Endometriosis Diagnostic Method Based on Serum Biomarkers and Clinical Variables. Biomolecules. 2023;13(7):1052. doi:https://doi.org/10.3390/biom13071052
3. Daoud E, Archer DF, Fabio Parazzini, Bárbara Herranz-Blanco. Validation of an In Vitro Diagnostic Test for Endometriosis: Impact of Confounding Medical Conditions and Lesion Location. International Journal of Molecular Sciences. 2024;25(14):7667-7667. doi:https://doi.org/10.3390/ijms25147667