The diagnosis of endometriosis through blood tests relies on the Ca-125 tumor marker, levels of which usually rise when the disease affects the ovaries. However, this test does not offer definitive results, as this marker can remain within normal ranges even when the pathology exists.
Furthermore, Ca-125 lacks diagnostic specificity, as its values also increase in the presence of fibroids, peritonitis, pregnancy, menstruation itself, or oncological processes.
For its part, the CA 19-9 antigen serves as a complementary indicator to evaluate the severity of endometriosis, although it has lower diagnostic sensitivity than the Ca-125 marker.
Read the full article on: Diagnosis of endometriosis: analytical and imaging tests ( 45).
By Elisa Pérez Larrea M.D., M.Sc. (gynecologist), Marta Barranquero Gómez B.Sc., M.Sc. (embryologist), Sara Salgado B.Sc., M.Sc. (embryologist) and Cristina Algarra Goosman B.Sc., M.Sc. (psychologist).
Last Update: 04/27/2026
