LAUSR

a decreased FE1. Thus, low elastase as a marker for steatorrhea was shown to have an excellent sensitivity but very poor specificity. Five (33%) of 15 LAPC patients had been prescribed PERT by medical specialists before entering the study, based on clinical symptoms or as standard procedure without measuring steatorrhea. Four of these did not suffer from steatorrhea and were therefore incorrectly treated with PERT (Fig. 1). Six (40%) of 15 LAPC patients did suffer from steatorrhea (fecal fat excretion above 20 g/d) of whom only 1 (17%) had been prescribed PERT adequately. Thus, PERT prescription, based on clinical symptoms or as standard procedure, was erroneously prescribed in 80% of patients, because these patients did not suffer from steatorrhea at all. In conclusion, our results show that fecal elastase fails to detect steatorrhea in patients with LAPC and is an inappropriate marker of exocrine pancreatic insufficiency in daily clinical practice. Besides this, prescription of PERT based on clinical symptoms or as a standard procedure resulted in inappropriate prescription of PERT in 80% of patients. Quantifying fecal fat loss in a 3 day fecal collection remains the recommended procedure to objectify steatorrhea and to adequately dose PERT prescriptions. However, because this test is cumbersome and time-consuming, we suggest to further optimize diagnostic criteria for objectifying pancreas dysfunction and PERT prescription in future research.