OP34.07: Prospective validation of the ultrasound‐based endometriosis staging system (UBESS)

To prospectively validate the recently developed Ultrasound Based Endometriosis Staging System (UBESS). Multicentre study of consecutive women presenting with chronic pelvic pain from July 2013 to December 2015. All women with symptoms of chronic pelvic pain +/− history of endometriosis underwent a detailed specialised transvaginal ultrasound (TVS) in a tertiary referral unit to stage the endometriosis prior to laparoscopy using the three stage UBESS. The findings from UBESS were correlated with surgical gold standard. 136/141 (96.5%) women with pre-operative TVS and laparoscopic outcomes were included in the final analysis. 48 (34%) of the women had a history of previous endometriosis with the mean age of diagnosis was 25.3 +/− 10.3 years. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value for the performance of UBESS at predicting level 1 laparoscopic surgery were 86.5/86.6/86.5/85.3/87.7%, level 2 were 84.4/67.6/89.7/67.6/89.7% and level 3 were 90.8/82.5/94.1/84.6/93.1%, respectively. UBESS can be used to pre-operatively stage women to the most appropriate level of laparoscopic endometriosis surgery required. It needs to be externally validated in order to assess its general applicability in other centres.