Endometriosis and Ca125

April 16, 2018
endometriosis and ca125

Endometriosis is a disease diagnosed via laparoscopic exam. This exam is the gold standard of diagnosis, where doctors examine the pelvic cavity and its surroundings looking for endometrial tissue. If found, they will also remove it during the procedure.  

While a non-invasive gold standard of diagnosis does not currently exist, however there is a promising biomarker known as Ca125 that may help in ruling in endometriosis as a potential cause for painful periods. 

What is Ca125

Ca125 (cancer antigen 125) is a biomarker traditionally used for ovarian cancer – monitoring therapies and to assess recurrence. It’s shown to be increased in women with endometriosis, and has therefore been proposed as a biomarker for endometriosis. This may help to reduce diagnostic time, offer treatment options, reduce progression of disease, and may even provide reassurance to women that they are not living with endometriosis. 

A 2017 study examined Ca125 levels in women who had symptoms of endometriosis (painful periods, painful sex and chronic pelvic pain). Ca125 levels and a laparoscopic exam (to confirm a histological diagnosis of endometriosis) were assessed in these women to determine the accuracy of Ca125 in the presence of endometriosis. Results showed that women with a high Ca125 level were also found to have endometriosis (in the absence of any other potential causes for disease). Moreover, they determined that a level of Ca125 greater than or equal to 30IU/mL would rule in endometriosis, while a measurement less than that would not rule out endometriosis. 

Next Steps

Measuring Ca125 levels may be a good first step in examining if endometriosis could be a cause of painful periods, painful sex and chronic pelvic pain. While it will not rule out endometriosis, it may lead to faster diagnostic times (the average time is 7-10 years), and help with its management. Naturopathic Doctors and Medical Doctors are able to run this test if you are hoping to rule endometriosis in before scheduling a laparoscopic exam. 


Hirsch M, Duffy J, Deguara C, Davis C, Khan K. Diagnostic accuracy of Cancer Antigen 125 (CA125) for endometriosis in symptomatic women: A multi-center study. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2017;210:102-107. doi:10.1016/j.ejogrb.2016.12.002.

Karimi-Zarchi M, Dehshiri-Zadeh N, Sekhavat L, Nosouhi F. Correlation of CA-125 serum level and clinico-pathological characteristic of patients with endometriosis. International Journal of Reproductive BioMedicine. 2016;14(11):713-718. doi:10.29252/ijrm.14.11.713.

Oliveira M, Raymundo T, Soares L, Pereira T, Demôro A. How to Use CA-125 More Effectively in the Diagnosis of Deep Endometriosis. Biomed Res Int. 2017;2017:1-6. doi:10.1155/2017/9857196.

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