['Accurate and precise interpretations of Focused Assessment with Sonography for Trauma (FAST) findings are important factors in managing trauma patients. The objectives were to analyze the influence of anechoic stripe (AS) size on interpretation accuracy by emergency physicians (EPs) and to assess the precision of FAST examination interpretation as a function of EP FAST experience.', 'A prospective comparison study of FAST examination interpretation by 11 emergency medicine faculty (FAC), nine community attending EPs (ATT), and nine senior emergency medicine residents (RES) was conducted; these physicians were then divided into more experienced and less experienced cohorts to assess precision. Participants interpreted video recordings of the four standard views from five FAST examinations (20 total video clips); each examination contained views with various AS sizes. Accuracy of FAST examination interpretation was calculated for each group stratified by size of AS. Precision (reproducibility) of FAST examination interpretation was assessed by calculating kappa values.', 'With large, moderate, or no AS, no significant differences in accuracy were found between groups. For small AS, significant differences in accuracy were found between the ATT and RES groups and between the combined FAC + ATT group and the RES group. Kappa was good to excellent when the nth and the (n + 1)th experienced physicians in the more experienced cohort were compared. kappa values reflected that the more experienced cohort was more precise than the less experienced cohort.'] Does anechoic stripe size influence accuracy of FAST examination interpretation?