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Test Code 5332 Reducing Substance, Feces

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Specimen Required

Supplies: Stool container, small (Random), 4 oz (T288)

Container/Tube: Stool container (T288)

Specimen Volume: 3 g

Collection Instructions:

1. Collect a loose, random stool specimen.

2. Freeze immediately.

Additional Information: If additional tests are ordered, aliquot and separate sample prior to freezing to allow 1 container per test.

Specimen Minimum Volume

2 g

Specimen Stability Information

Specimen Type Temperature Time
Fecal Frozen 7 days

Reference Values

Negative or trace

Day(s) and Time(s) Performed

Monday through Saturday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
UREDF Reducing Substance, F 11060-1


Result ID Test Result Name Result LOINC Value
6215 Reducing Substance, F 11060-1

Clinical Information

Testing for fecal reducing substances (carbohydrates) aides in determining the underlying cause of diarrhea. Elevations in fecal reducing substances helps distinguish between osmotic diarrhea caused by abnormal excretion of various sugars as opposed to diarrhea caused by viruses and parasites. Increased reducing substances in stool are consistent with, but not diagnostic of, primary or secondary disaccharidase deficiency (primarily lactase deficiency) or intestinal monosaccharide malabsorption. Similar intestinal absorption deficiencies are associated with short bowel syndrome and necrotizing enterocolitis.


Negative: negative

Normal: ≤0.25 g/dL (trace)

Suspicious: >0.25 to 0.50 g/dL (grade 1)

Abnormal: >0.50 g/dL (grade 2-4)

Clinical Reference

1. Siddiqui HA, Salwen MJ, Shaikh MF, et al: Laboratory Diagnosis of Gastrointestinal and Pancreatic Disorders. In Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd edition. Elsevier Inc, St. Louis, MO 2017;22:306-323 e2

2. Branski D: Disorders of Malabsorption. In Nelson Textbook of Pediatrics. Edited by RM Kleigman, BF Stanton, JW St. Geme, et al. Elsevier In., Philadelphia, PA, 2016, pp1831-1850.e2

3. Bhatia J, Prihoda AR, Richardson CJ: Parenteral antibiotics and carbohydrate intolerance in term neonates. Am J Dis Child 1986;140:111-113

4. Book LS, Herbst JJ, Jung AL: Carbohydrate malabsorption in necrotizing enterocolitis. Pediatrics 1976;57:201-204

5. Krom FA, Frank CG. Clinitesting neonatal stools. Neonatal Network 1989;8(2):37-40

6. Qualitative Methods for Total Reducing Substances. In Tietz Textbook of Clinical Chemistry, Second Edition. 1994, pp 968-969

Method Name

Benedict's Copper Reduction Reaction


If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Client Test Request (T728) with the specimen.