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HelpTest Code 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
Method Name
Benedict's Copper Reduction Reaction
Performing Laboratory
Mayo Clinic Laboratories in Rochester
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 |
Reject Due To
| Urine and feces mixed Feces collected in any preservative or fixative |
Reject |
Reference Values
Negative or trace
Day(s) Performed
Monday through Saturday
CPT Code Information
84376
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
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.
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)