The reproducibility of the revised American Fertility Society classification of endometriosis

Abstract

To assess the degree of intraobserver and interobserver variability in endometriosis staging using the revised American Fertility Society (AFS) classification of endometriosis. Videotapes of laparoscopies of 20 patients with endometriosis were each scored twice by five observers. The reproductive endocrine unit of a tertiary care, university-affiliated hospital. Five subspecialty-certified reproductive endocrinologists. None. Variability in assigned score was measured for each of the five components of the AFS classification, as well as total scores and stage of endometriosis. There was considerable variability in the scores assigned to each videotape, both by the same observer and by different observers. The grand total score, which ranged from 0 to 90, varied with an SD of 13.44 when a single patient was rated twice by the same observer and varied with an SD of 17.12 when a single patient was rated by two different observers. Among individual components of the score, the greatest variability occurred in endometriosis of the ovary and cul-de-sac obliteration, with less variability observed for peritoneum endometriosis and for ovarian and tubal adhesions. Comparison of intraobserver and interobserver scores resulted in a change in endometriosis stage in 38% and 52% of patients, respectively. There were statistically significant differences in mean endometriosis scores among the observers in four of the five anatomic categories examined. Intraobserver and interobserver variability was high for ovarian endometriosis and cul-de-sac subscores using the revised AFS classification of endometriosis.