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HelpTest ID UREDF Reducing Substance, Feces
Reporting Name
Reducing Substance, FUseful For
Assisting in the differentiation between osmotic and nonosmotic diarrhea
Screening test for:
-Diarrhea from disaccharidase deficiencies, (eg, lactase deficiency)
-Monosaccharide malabsorption
Specimen Type
FecalSpecimen Required
Supplies: Stool container, Small (Random), 4 oz Random (T288)
Container/Tube: Fecal container
Specimen Volume: 3 g
Collection Instructions:
1. Collect a loose, unpreserved, random fecal 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 | Special Container |
|---|---|---|---|
| Fecal | Frozen | 7 days |
Reference Values
Negative or trace
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84376
Clinical Information
Fecal reducing substances (carbohydrates) aids in determining the underlying cause of diarrhea. Elevations in fecal reducing substances help 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.
Interpretation
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)
Cautions
This test has poor sensitivity for oligosaccharides.
Antibiotics can alter the intestinal flora and affect acid production.
False-positive reactions due to drugs (salicylates, penicillin, ascorbic acid, nalidixic acid, cephalosporins, and probenecid) are possible.
Feces may be contaminated with urine, in which case glycosuria will give false-positive results.
Diaper collections can be falsely decreased as the fluid portion containing water soluble sugars is absorbed into the diaper.
Bacteria in specimen consumes sugars resulting in falsely decreased values. Specimen should be frozen within 30 minutes of collection.
Clinical Reference
1. Siddiqui HA, Salwen MJ, Shaikh MF, Bowne WB: Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. Elsevier; 2017:306-323
2. Branski D: Disorders of malabsorption. In: Kliegman RM, Stanton BF, St. Geme JW, eds. Nelson Textbook of Pediatrics. Elsevier; 2016:1831-1850
3. Bhatia J, Prihoda AR, Richardson CJ: Parenteral antibiotics and carbohydrate intolerance in term neonates. Am J Dis Child. 1986;140(2):111-113
4. Book LS, Herbst JJ, Jung AL: Carbohydrate malabsorption in necrotizing enterocolitis. Pediatrics. 1976;57(2):201-204
5. Krom FA, Frank CG: Clinitesting neonatal stools. Neonatal Network. 1989 Oct;8(2):37-40
6. Burtis CA, Ashwood ER: Qualitative methods for total reducing substances. In: Tietz Textbook of Clinical Chemistry. 2nd ed. 1994;968-969
Method Description
Copper sulfate in the tablet reacts with reducing substances converting cupric sulfate to cuprous oxide.(Package insert: AimTab Reducing Substances Tablets. Germaine Laboratories, Inc; 12/2015)
Reject Due To
| Urine and feces mixed Feces collected in any preservative or fixative |
Reject |
NY State Approved
YesMethod Name
Benedict's Copper Reduction Reaction
Forms
If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.
Day(s) Performed
Monday through Saturday