The detection rates varied substantially depending on the applied fluid volume and the examined pouch. The Morrison pouch showed the highest detection rate of 77.2% with 1500 ml intraabdominal fluid, whereas the Koller pouch was still negative at 62.9% with that amount of free fluid. If the FAST exam is positive, i.e. free fluid was detected in any pouch of an abdominal trauma patient, the amount of fluid needs to be considered as significant. The rate of detection can be improved if the pouches are assesed in two planes (i.e. transversal and longitudinal).