What is the workup for a patient presenting with loose, white stools, also known as steatorrhea (excess fat in feces) or acholic stools ( stools lacking bile)?

From the Guidelines

The workup for loose white stool should begin with a comprehensive history and physical examination, followed by laboratory and imaging studies, prioritizing tests for celiac disease, bile acid diarrhea, and pancreatic insufficiency, as these are common causes of chronic diarrhea and malabsorption 1. The initial evaluation should include a detailed history to establish the likelihood of organic disease, distinguish malabsorptive from colonic/inflammatory forms of diarrhea, and assess for specific causes of diarrhea, such as family history, previous surgery, pancreatic disease, systemic disease, alcohol use, diet, and medication use 1. Key laboratory tests should include:

• Complete blood count
• Comprehensive metabolic panel
• Stool studies, including fecal fat, culture, ova and parasites, and Clostridium difficile testing
• Pancreatic enzyme levels, such as amylase and lipase
• Testing for celiac disease with IgA tissue transglutaminase and a second test to detect celiac disease in the setting of IgA deficiency, as recommended by the AGA 1 Imaging studies, such as abdominal ultrasound and CT scan, may be necessary to evaluate the liver, gallbladder, and pancreas, and to assess for biliary obstruction or other structural abnormalities. For persistent cases without clear etiology, colonoscopy with biopsies might be warranted to rule out inflammatory or malignant causes of diarrhea. Treatment depends on the underlying cause, and may include enzyme replacement therapy for pancreatic insufficiency, addressing specific deficiencies for malabsorption, and appropriate antimicrobial therapy for infections.

From the Research

Loose White Stool Workup

• The workup for loose white stool may involve various tests to determine the underlying cause of the condition.
• According to 2, stool diagnostic tests can help identify the cause of diarrhea, including loose white stool.
• The tests may include:
  • Fecal elastase 1 (FE1) to diagnose pancreatic exocrine insufficiency (PEI) 3
  • Fecal fat estimation (FFE) to diagnose PEI 3
  • Stool tests for bacterial, viral, or protozoal infections 2
  • Glutamate dehydrogenase test for Clostridioides difficile infection 2
  • Nucleic acid amplification test (for toxin B) or enzyme immunoassays for toxin A or B to distinguish infection from carrier state 2
• A comprehensive stool biochemical analysis, including osmolality, pH, and electrolytes, can help differentiate between osmotic and secretory diarrhea and identify laxative abuse 2
• Specific stool diagnostic tests for bile acid diarrhea and exocrine pancreatic insufficiency can lead to specific diagnosis and treatments 2
• The Bristol Stool Chart (BSC) can be used to evaluate fecal consistency, with a score of 5 or more indicating loose stools 4
• A breath test can be used to detect bacterial overgrowth, lactose or fructose/sorbitol malabsorption, and/or a cholestyramine test to detect bile acid malabsorption 4

Diagnostic Approach

• The diagnostic approach for loose white stool may involve a combination of medical history, physical examination, and laboratory tests.
• According to 4, patients with loose stools (BSC ≥5) may undergo a breath test to detect bacterial overgrowth, lactose or fructose/sorbitol malabsorption, and/or a cholestyramine test to detect bile acid malabsorption.
• The results of these tests can help guide further diagnosis and treatment.
• It is essential to consider the clinical severity and quality of life (QoL) of patients with loose stools, as they may experience significant impairment in their daily lives 4