KRAS and chronic kidney disease: In that study, PEI was determined by FE-1 and showed no significant differences between subjects with or without K-ras mutation [22].FE-1 level has recently been highlighted as an indicator of pancreatic exocrine function, and levels of FE-1 lower than 200 μg/g of stool indicates the existence of PEI (the concentration of 100 to 200 μg/g stool indicating mild to moderate PEI, and the concentration below 100 μg/g stool indicating severe PEI) [23].FE-1 levels have been assessed in pancreatitis, pancreatic cancer, trauma, or chronic renal failure.