pancreatic deficiency symptomselevated pancreatic elastaseexocrine pancreatic deficiencypancreatic elastase levelspancreatic amylase deficiencypancreatitis vitamin deficiencypancreatic enzyme deficiency symptomsfaecal pancreatic elastasestool pancreatic elastaseelastase 1pancreatic elastase 1 testfaecal elastase chronic pancreatitis