What is the next step in managing a patient with episodic left upper quadrant pain and steatorrhea, suspected of having pancreatic exocrine insufficiency, with a clear CT with contrast?

Next Step: Perform Fecal Elastase-1 Testing

When CT with contrast is clear in a patient with episodic left upper quadrant pain and steatorrhea suspected of having pancreatic exocrine insufficiency, proceed directly with fecal elastase-1 testing as the most appropriate initial diagnostic test for EPI. 1

Diagnostic Rationale

The absence of structural abnormalities on CT imaging does not exclude exocrine pancreatic insufficiency, as cross-sectional imaging cannot diagnose EPI—it only identifies underlying pancreatic pathology 1. A clear CT means you have ruled out obvious structural causes (chronic pancreatitis changes, masses, ductal obstruction), but functional pancreatic insufficiency can exist without visible morphological changes.

Fecal Elastase-1 Testing Protocol

• Obtain fecal elastase-1 on semi-solid or solid stool specimens only, as liquid or watery stool produces false positive results 1
• Interpretation thresholds 1:
  • <100 μg/g = good evidence of EPI (proceed to treatment)
  • 100-200 μg/g = indeterminate (consider additional testing)

  • 200 μg/g = normal (EPI unlikely)

If Fecal Elastase-1 Confirms EPI (<100 μg/g)

Initiate pancreatic enzyme replacement therapy (PERT) immediately to prevent malnutrition-related morbidity and mortality 2, 1:

• Starting dose: 40,000 USP units of lipase with each meal, and 20,000 units with snacks 1
• Timing: Take enzymes during meals, not before or after 1
• All enteric-coated formulations are equally effective at equivalent doses 1

Baseline Assessments Before Starting PERT

Obtain the following to monitor treatment response 2:

• Body mass index and weight
• Fat-soluble vitamin levels (A, D, E, K)
• Nutritional markers: prealbumin, retinol-binding protein, B12, folate, thiamine, selenium, zinc, magnesium
• Hemoglobin A1c (screen for diabetes)
• Dual-energy x-ray absorptiometry (DEXA) scan for bone density 2

If Fecal Elastase-1 is Indeterminate (100-200 μg/g)

Consider additional testing in select cases 1:

• Fecal fat quantification (72-hour collection)—though rarely practical for routine use 1, 3
• Direct pancreatic function tests if available and clinical suspicion remains high 1
• Empiric trial of PERT may be reasonable given the clinical presentation of steatorrhea

Common Pitfalls to Avoid

• Do not assume a clear CT rules out EPI—functional insufficiency precedes structural changes in many cases 1
• Do not test fecal elastase-1 on watery/liquid stool—this produces false positives and will mislead your diagnosis 1
• Do not delay PERT initiation once EPI is confirmed—early treatment prevents long-term malnutrition complications and improves quality of life 2
• Do not use CT or MRI alone to diagnose EPI—these modalities identify structural disease but cannot assess exocrine function 1

Monitoring Treatment Success

Assess response to PERT by 2, 1:

• Reduction in steatorrhea and gastrointestinal symptoms
• Weight gain and improvement in muscle mass
• Normalization of fat-soluble vitamin levels
• If inadequate response, double the PERT dose and consider adding proton pump inhibitors to optimize enzyme activity 1, 3