What is the next step in evaluating a 41-year-old female with three months of steatorrhea (floating stools) and normal laboratory results, including complete blood count (CBC), comprehensive metabolic panel (CMP), iron panel, liver enzymes, and ultrasound of the liver, gallbladder, and most of the pancreas?

Evaluation of Steatorrhea in a 41-Year-Old Female with Normal Initial Workup

You should obtain fecal elastase testing as the next diagnostic step, and if normal, proceed with endoscopic ultrasound (EUS) or CT imaging to evaluate for pancreatic malignancy, given the patient's age over 40 years with unexplained steatorrhea. 1

Rationale for Pancreatic Cancer Screening

At age 41 with unexplained steatorrhea, this patient meets criteria for evaluation of underlying pancreatic malignancy. The AGA guidelines specifically recommend CT or EUS in patients with unexplained pancreatitis or pancreatic symptoms who are older than 40 years of age, as they are at increased risk for underlying pancreatic malignancy 1. While your patient doesn't have pancreatitis, the principle of age-based risk stratification for pancreatic pathology applies to unexplained steatorrhea as well.

Why Standard Ultrasound Is Insufficient

• Abdominal ultrasound has significant limitations for pancreatic visualization, particularly for the pancreatic body and tail, and cannot reliably exclude pancreatic masses 1
• The fact that "most of pancreas" was visualized means portions were not adequately assessed, leaving diagnostic uncertainty 1
• Cross-sectional imaging cannot directly diagnose exocrine pancreatic insufficiency (EPI), but plays a critical role in identifying structural pancreatic disease including malignancy 1

Recommended Diagnostic Algorithm

Step 1: Fecal Elastase Testing

• Fecal elastase-1 (FE-1) is the preferred non-invasive test for pancreatic insufficiency due to its simplicity, low cost, and acceptable reliability 1
• Values <200 mg/g indicate abnormal function, with <100 mg/g more consistent with EPI, and <50 mg/g indicating severe EPI 1
• This test is not affected by pancreatic enzyme replacement therapy, making it ideal for initial assessment 1
• Normal FE-1 would argue against pancreatic insufficiency as the cause of her symptoms 2

Step 2: Advanced Pancreatic Imaging

If fecal elastase is abnormal OR if clinical suspicion remains high despite normal elastase:

• Endoscopic ultrasound (EUS) is the preferred modality for detailed pancreatic evaluation in patients over 40 with unexplained symptoms 1
• CT enterography or MRI/MRCP are acceptable alternatives for comprehensive pancreatic and small bowel assessment 1
• These studies can identify early pancreatic masses, chronic pancreatitis changes, and structural abnormalities not visible on standard ultrasound 1

Step 3: Consider Small Bowel Evaluation

Given the normal labs effectively exclude significant small bowel malabsorption:

• Normal CBC rules out anemia from iron, folate, or B12 malabsorption 3
• Normal albumin excludes protein malabsorption from significant small bowel disease 3
• Normal iron panel directly excludes iron malabsorption, the most sensitive early marker of small bowel pathology 3
• If pancreatic workup is negative, consider celiac serology (tissue transglutaminase antibodies) and upper endoscopy with duodenal biopsies 1

Important Clinical Context

Why "Floating Stools" May Not Indicate True Steatorrhea

• Floating stools are nonspecific and often not indicative of true fat malabsorption 1
• True steatorrhea typically requires >7 g/day of fecal fat excretion and presents with greasy, difficult-to-flush stools 1, 4
• Response to empiric pancreatic enzyme therapy is unreliable for diagnosis and may represent placebo effect or mask other disorders like celiac disease 1

Red Flags That Would Escalate Urgency

• Weight loss is the most important indicator of organic disease and warrants aggressive workup 3
• Development of jaundice, persistent abdominal pain, or new-onset diabetes would significantly increase concern for pancreatic malignancy 1
• Elevated inflammatory markers (ESR, CRP) have high specificity for organic disease 3

Tests to Avoid

• Do not use serum pancreatic enzymes (lipase, amylase, trypsin) for diagnosing chronic pancreatic insufficiency, as they lack sensitivity until disease is far advanced 2, 1
• Avoid empiric pancreatic enzyme replacement as a diagnostic test, as it is expensive, unreliable for diagnosis, and may delay correct diagnosis 1
• Quantitative 72-hour fecal fat collection is poorly reproducible, burdensome, and non-diagnostic for the underlying cause 1

Summary of Approach

Your patient's age (41 years), duration of symptoms (3 months), and incomplete pancreatic visualization on ultrasound justify further evaluation for pancreatic pathology, including malignancy. 1 The combination of fecal elastase testing followed by EUS or CT provides the most efficient pathway to either identify pancreatic insufficiency and its underlying cause, or confidently exclude significant pancreatic disease and redirect evaluation toward other causes of her symptoms 1.