Chronic diarrhea laboratory findings
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Chronic diarrhea Microchapters |
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Diagnosis |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Omodamola Aje B.Sc, M.D. [2]
Overview
Laboratory Findings
Blood Tests
Initial laboratory tests should include a complete blood count to evaluate for anemia and an abnormal white blood cell count, as well as electrolytes, thyroid tests, and serological tests for celiac disease.
Stool Analysis
Fecal leukocytes
The presence of white blood cells in the stool has a sensitivity of 70% and a specificity of 50% for detecting inflammation in studies of infectious diarrhea. Fecal white blood cells can be present in both infectious colitis and inflammatory bowel diseases such as ulcerative colitis, Crohn’s disease, and microscopic colitis.
Fecal lactoferrin
This is an iron-binding glycoprotein that is a major component of the secondary granules of polymorphonuclear neutrophils and is secreted by most mucosal membranes. Fecal lactoferrin levels have never been evaluated in the workup of chronic diarrhea.
Fecal occult blood
The sensitivity and specificity of stool guaiac cards for detecting inflammatory or neoplastic causes of diarrhea have not been studied.
Stool electrolytes
Measuring stool potassium and sodium concentrations can determine the stool osmotic gap. For secretory diarrhea, the osmotic gap is less than 50 mOsm/kg. In osmotic diarrhea, the osmotic gap is greater than 50 mOsm/kg.