From the Guidelines
The workup for intestinal malabsorption should begin with a thorough history and physical examination, followed by initial laboratory tests including complete blood count, comprehensive metabolic panel, albumin, prealbumin, iron studies, vitamin B12, folate, and fat-soluble vitamin levels (A, D, E, K) as recommended by recent guidelines 1. The initial step in evaluating intestinal malabsorption involves assessing the patient's clinical presentation and performing basic laboratory tests to identify potential nutritional deficiencies.
- Stool studies are essential, particularly fecal fat quantification via a 72-hour stool collection while on a 100g fat diet, which remains the gold standard for diagnosing fat malabsorption.
- Additional stool tests should include fecal elastase, as recommended by the British Society of Gastroenterology 1, calprotectin, and testing for infectious causes.
- Serologic testing for celiac disease with tissue transglutaminase antibodies and total IgA is recommended for all patients, given the high prevalence of celiac disease as a cause of chronic malabsorption 1.
Imaging and Endoscopy
Imaging studies may include abdominal ultrasound or CT scan to evaluate for pancreatic abnormalities or other structural issues.
- MR enterography is recommended for evaluation of small bowel abnormalities depending on availability, with a strong recommendation and high level of evidence 1.
- Video capsule endoscopy (VCE) is also recommended for assessing small bowel abnormalities, depending on local availability, with a strong recommendation and high level of evidence 1.
- Endoscopic procedures are often necessary, with upper endoscopy and duodenal biopsies being crucial for diagnosing celiac disease, small intestinal bacterial overgrowth, and other mucosal abnormalities.
Specialized Tests
For suspected small intestinal bacterial overgrowth, an empirical trial of antibiotics is recommended, as there is insufficient evidence to support routine hydrogen or methane breath testing 1. In cases where the diagnosis remains unclear, specialized tests such as D-xylose absorption test, SeHCAT scan for bile acid malabsorption, or wireless motility capsule may be considered. This comprehensive approach helps identify the underlying cause of malabsorption, which is essential for directing appropriate treatment and improving patient outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Intestinal Malabsorption Workup
The workup for intestinal malabsorption involves a series of diagnostic tests to identify the underlying cause of malabsorption. The following are some of the key steps involved in the workup:
- Medical and pharmacological history to identify risk factors 2
- Physical examination and blood tests to confirm malabsorption
- Stool studies to confirm fat malabsorption 3
- Endoscopy with small-bowel biopsies and aspirates for bacterial culture 3
- Assessment of pancreatic function 3
- Barium radiograph of the small bowel to look for anatomical abnormalities 3
- Serological markers for celiac sprue 3
- Duodenal biopsy for diagnosis of celiac sprue 3
Diagnostic Tests
The following diagnostic tests may be used to investigate malabsorption:
- Fecal fat or fecal elastase-1 tests for exocrine pancreatic insufficiency 4
- 75selenium homotaurocholic acid test for bile acid malabsorption 4
- Breath tests for lactose intolerance and small intestinal bacterial overgrowth 4, 2
- Jejunal biopsy for small intestinal bacterial overgrowth 4
- Non-invasive functional tests and radiological imaging 2
Management
The management of malabsorption depends on the underlying cause and may involve:
- Gluten avoidance for celiac disease 4
- Lactose avoidance for lactose intolerance 4
- Pancreatic enzyme replacement for exocrine pancreatic insufficiency 4
- Antibiotics for small intestinal bacterial overgrowth 4
- Nutritional support with oral supplements, enteral or parenteral nutrition 2, 5
- Medicinal treatment options for diarrhea in malabsorption, such as loperamide, codeine, cholestyramine, or antibiotics 5