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HelpTest ID UREDF Reducing Substance, Feces
Useful For
Diagnosing intestinal malabsorption in children
Assisting in the differentiation between osmotic and nonosmotic diarrhea
Screening test for:
-Diarrhea from disaccharidase deficiencies, (eg, lactase deficiency)
-Monosaccharide malabsorption
Method Name
Clinitest Reagent Tablets
Reporting Name
Reducing Substance, FSpecimen Type
FecalContainer/Tube: Stool container (Supply T288)
Specimen Volume: 3 g
Collection Instructions:
1. Collect a loose, random stool specimen.
2. Freeze immediately.
3. If collecting from an infant, use nonabsorbent diapers to collect the specimen. If stool is collected in a disposable diaper, the solid and liquid stool must be combined. The liquid portion of the stool can be aspirated from the diaper using a syringe or alternatively can be expressed from the diaper into a cup. If a diaper has gel absorption, a cotton ball will be necessary to collect the liquid portion of the stool.
4. It is critical that urine is not also mixed with the specimen. Urine will interfere with the results.
Specimen Minimum Volume
2 g
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Fecal | Frozen | 7 days |
Clinical Information
Sugars (eg, glucose, galactose, fructose, maltose, lactose, and pentose) are characterized as reducing substances based on their ability to reduce cupric ions to cuprous ions.
Fecal reducing substances may be increased in carbohydrate malabsorption syndromes.
Reference Values
Negative or trace
Cautions
A number of other compounds also are capable of reducing cupric ions to cuprous ions and can cause false-positives.
Ambient transport temperatures result in growth of bacteria. Bacteria consume reducing substances, which can result in false-negative results, so ambient specimens are rejected.
This test has poor sensitivity for oligosaccharides and poor sensitivity from diaper stools because fluid is reabsorbed into the diaper. Testing of only the solid portion of the stool will give a falsely-low reading since the liquid portion of the stool contains the water-soluble sugars.
Possible interferences include: salicylates, penicillin, choral hydrate, menthol, phenol, streptomycin, para-aminosalicylic acid, isoniazid, ascorbic acid, cephalosporins, and probenecid.
Day(s) Performed
Monday through Friday
Report Available
1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been modified from the manufacturer’s instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
84376