From the Guidelines
The elastase stool test is the most appropriate initial test for diagnosing exocrine pancreatic insufficiency (EPI) and should be performed on a semi-solid or solid stool specimen, with a level <100 mg/g of stool providing good evidence of EPI, as recommended by the AGA clinical practice update 1. When interpreting the results of the elastase stool test, it is essential to consider the clinical context and the patient's symptoms, such as steatorrhea, weight loss, and bloating.
- The test is valuable because pancreatic elastase is highly stable during intestinal transit and isn't degraded, making it a reliable marker of pancreatic function.
- Normal elastase levels are generally above 200 μg/g of stool, while levels between 100-200 μg/g suggest moderate pancreatic insufficiency, and levels below 100 μg/g indicate severe insufficiency, as supported by the guidelines for the investigation of chronic diarrhoea in adults 1.
- The test is unaffected by simultaneous enzyme therapy or diet and requires only a single stool sample, making it a convenient and non-invasive method for assessing pancreatic exocrine function.
- However, the test should be used with care in patients with liquid stool, as this can lead to false positive results due to dilution, as noted in the guidelines for the investigation of chronic diarrhoea in adults 1.
- Once EPI is diagnosed, treatment with pancreatic enzyme replacement therapy (PERT) is required to prevent complications related to fat malabsorption and malnutrition, and to improve quality of life, as recommended by the AGA clinical practice update 1.
From the Research
Elastase Stool Test Overview
- The elastase stool test, also known as the fecal elastase-1 (FE-1) test, is a non-invasive method for evaluating pancreatic function 2, 3, 4.
- This test measures the level of elastase-1, a specific human protease, in stool, which is a reliable indicator of pancreatic exocrine function 4.
Clinical Applications
- The FE-1 test is useful for screening patients with symptoms suggestive of pancreatic disease, such as abdominal pain or diarrhea 2.
- It is also used to determine the presence of pancreatic exocrine insufficiency (PEI) in patients with established pancreatic disease, such as chronic pancreatitis or cystic fibrosis 2, 5, 3.
- The test is particularly useful in disorders not commonly tested for PEI but have a known association with this disorder 2.
Advantages and Limitations
- The FE-1 test is non-invasive, less time-consuming, and unaffected by pancreatic enzyme replacement therapy 2, 4.
- It is a sensitive, specific, and relatively inexpensive test, making it an attractive alternative to direct pancreatic stimulation tests 3, 4.
- However, it cannot be considered the gold-standard method for the functional diagnosis of PEI 2.