Test ID: CLF
Chloride, Random, Feces
Useful For 
Suggests clinical disorders or settings where the test may be helpful
Diagnosis of congenital hypochloremic alkalosis with chloridorrhea
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Chloride is normally co-transported with sodium from the small intestine into the vascular spaces; chloride is highly conserved by this process.
Fecal chloride concentration usually represents a very small fraction of fecal osmolality. Carbonate, sulfate, carbohydrate, and bile acids are the predominant anions present in fecal water.
Fecal chloride concentration is not proportional to serum chloride content.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
0-15 years: not established
> or =16 years: 0-39 mEq/kg
Interpretation Provides information to assist in interpretation of the test results
Normal fecal chloride concentration is <10 mEq/kg, or daily excretion is <2 mEq/24 hours.
Modest increases (2x) in fecal chloride concentration and excretion rate may be observed when fecal sodium is elevated in association with a high osmotic gap (osmotic diarrhea).
Fecal chloride concentration or daily excretion rate are markedly elevated (7-10 times normal) in association with congenital hypochloremic alkalosis with chloridorrhea.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test will be performed only on watery stools (diarrhea).
In the event a formed stool is submitted, the test will not be performed, and the report will indicate: "A formed stool specimen was submitted for analysis. This test was not performed because it only has clinical value if performed on a naturally occurring watery stool specimen."
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Phillips S, Donaldson L, Geisler K, et al: Stool composition in factitial diarrhea: a 6-year experience with stool analysis. Ann Intern Med 1995;123:97-100
2. Holmberg C: Congenital chloride diarrhea. Clin Gastroenterol 1986;15:583-602
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