Result Test Name
CHLORIDE FECES
Laboratory
QUEST LAB
Result Test Code
12386004860
Laboratory Test Name
QUEST ELECTROLYTES FECES
Reportable Test Name
-
Result LOINC
-
Collection Container
STERILE CONTAINER
Units
-
Collection Requirements
Preferred Specimen(s) 10 mL random watery liquid fecal collected in a plastic screw-cap container or 24-hour 48-hour or 72-hour watery liquid fecal collected in a plastic screw-cap container Minimum Volume 2 mL Collection Instructions Submit a frozen specimen of watery liquid feces in a plastic screw-cap container. Keep feces refrigerated during collection and transport frozen. Only watery liquid feces are an acceptable specimen. In the event a formed fecal specimen is submitted the test will not be performed and will be cancelled. Note: Specimen must be shipped frozen to reduce the odor during shipping and to minimize the risk of the container rupturing due to gas accumulation. This test only has clinical utility if performed on a watery fecal specimen.
Container Temp
Frozen (2)
Container Volume
2.000
Test Info
Electrolytes Feces - This panel measures sodium potassium and chloride in liquid stool. Measurements of electrolytes and osmotic gap in liquid stool help differentiate between secretory and osmotic diarrhea and thus guide further evaluation of chronic diarrhea [12]. Diarrhea can be categorized as secretory or osmotic depending on how the water content of stool is drawn in the intestine lumen. Secretory diarrhea is caused by defective electrolyte absorption that increases the stool's electrolyte levels. Conditions associated with secretory diarrhea include infection neuroendocrine tumors congenital chloridorrhea intestinal resection and diffuse mucosal disease [1]. Osmotic diarrhea is caused by the osmotic effect of a substance that retains water in the intestine lumen and leads to decreased electrolyte levels in the stool. Conditions associated with osmotic diarrhea include ingesting poorly absorbed solutes (eg sorbitol mannitol and laxatives containing magnesium) and enzyme dysfunction (eg lactose intolerance) [2]. Osmotic gap calculated as the difference between the stool osmolality and twice the sum of the stool sodium and potassium levels is useful in assessing the contribution of stool electrolytes to osmolality and differentiating between secretory and osmotic diarrhea [12].A theoretical fecal osmolality approximately the same as plasma osmolality (290 mOsm/kg) is used in the calculation. Measurement of chloride in liquid stool aids in the diagnosis of congenital or secondary chloridorrhea which is characterized by increased excretion of chloride in stool. Low levels of chloride in liquid stool may also be seen in sodium sulfate-induced diarrhea [2]. The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings. References 1. Schiller LR. Pract Res Clin Gastroenterol. 2012;26(5):551-562. 2. Block DR et al. Body fluids. In: Rifai R et al. eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier Inc; 2022.
Shipping Instructions
Transport Container Plastic leak-proof container Transport Temperature Frozen Specimen Stability Room temperature: Unacceptable Refrigerated: 7 days Frozen: 30 days Reject Criteria Specimens in paint cans Formed stool Specimens received refrigerated