What are the next steps for further testing for low fecal elastase (Pancreatic Elastase) levels?

From the Guidelines

Further testing for low fecal elastase should include pancreatic imaging with either contrast-enhanced CT scan or MRI/MRCP to evaluate for structural abnormalities of the pancreas, as recommended by the most recent guidelines 1. This approach is supported by the American Gastroenterological Association (AGA) clinical practice update on the epidemiology, evaluation, and management of exocrine pancreatic insufficiency, which suggests that imaging studies can identify chronic pancreatitis, pancreatic atrophy, calcifications, or masses that may explain pancreatic exocrine insufficiency 1. Some key points to consider when interpreting fecal elastase results include:

• A fecal elastase level <100 mg/g of stool provides good evidence of exocrine pancreatic insufficiency (EPI), while levels of 100–200 mg/g of stool are indeterminate for EPI 1
• The test should be performed on a semi-solid or solid stool specimen, as liquid stool can lead to false positive results 1
• Fecal elastase testing can be performed while on pancreatic enzyme replacement therapy (PERT) 1
• Response to a therapeutic trial of pancreatic enzymes is unreliable for EPI diagnosis, and appropriate testing (e.g., fecal elastase) is suggested before initiating therapy with PERT 1 Additional testing may include:
• Endoscopic ultrasound (EUS) to provide detailed images of the pancreatic parenchyma and ductal system
• Direct pancreatic function testing with secretin stimulation test at specialized centers, if imaging is normal but clinical suspicion remains high
• Screening for conditions associated with pancreatic insufficiency, including cystic fibrosis, celiac disease, and inflammatory bowel disease
• A trial of PERT, such as pancrelipase (Creon), at doses of 25,000-40,000 lipase units with meals, which can be both diagnostic and therapeutic 1

From the Research

Further Testing for Low Fecal Elastase

• Low fecal elastase-1 (FE-1) results are suggestive of pancreatic insufficiency, but watery diarrhea may lead to falsely low results 2
• A study found that 71% of patients with low FE-1 results in watery samples had normal results when measured in a formed sample 2
• The diagnostic accuracy of fecal elastase-1 measurement in detection of exocrine pancreatic insufficiency (EPI) is not clear, with a pooled sensitivity value of 0.77 and specificity value of 0.88 compared to secretin stimulation test 3
• Normal level of elastase-1 (above 200 mcg/g) can rule out EPI in patients with a low probability of this disorder, but an abnormal level of elastase-1 (below 200 mcg/g) has a high false-positive rate 3
• Transient small bowel damage resulting from enteric pathogens may cause decreased exocrine pancreatic enzyme secretion, leading to low fecal elastase levels 4

Implications for Testing and Treatment

• Reporting practice for FE-1 values in watery samples was changed to not report values ≤199 ug/g, which appears clinically safe and has potentially reduced inappropriate diagnoses and prescribing 2
• Pancreatic enzyme replacement therapy (PERT) is safe and effective at treating pancreatic exocrine insufficiency, but starting doses and administration methods should be carefully considered 5, 6
• Determining if a patient is malabsorbing due to pancreatic exocrine insufficiency is crucial in deciding if PERT is appropriate, and methods for determining pancreatic insufficiency include fecal elastase-1 measurement 6