Strengths and limitations of diagnostic tools for endometriosis and relevance in diagnostic test accuracy research

Endometriosis is a chronic systemic disease that can cause pain, infertility, and reduced quality of life in those affected. Diagnosing endometriosis remains challenging, which yields diagnostic delays for patients. Diagnostic test accuracy research in endometriosis can be difficult due to verification bias, as not all patients with endometriosis undergo definitive diagnostic testing. The purpose of this state-of-the-art review is to provide a comprehensive update on the strengths and limitations of the diagnostic modalities used in endometriosis and discuss the relevance of diagnostic test accuracy research pertaining to each. We performed a comprehensive literature review of the following methods: clinical exam including history and physical examination, biomarkers, diagnostic imaging, surgical diagnosis, and histopathology. Our review suggests that although non-invasive diagnostic methods such as clinical assessment, ultrasound and MRI do not yet formally qualify as replacement tests for surgery in diagnosing all subtypes of endometriosis, they are likely appropriate for advanced states of endometriosis. We also demonstrate through our review that all methods have strengths and limitations, leading to our conclusion that there should not be a single gold standard diagnostic method for endometriosis, but rather multiple accepted diagnostic methods depending on the circumstances.