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Epic Test Code LAB442 Reducing Substance, Feces

Additional Codes

MML Code: UREDF

LIS Code: SRS

NY State Approved

Yes

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Reducing Substance, F

Method Name

Benedict's Copper Reduction Reaction

Specimen Stability Information

Specimen Type Temperature Time Special Container
Fecal Frozen 7 days


Specimen 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 Type

Fecal

Specimen Minimum Volume

2 g

Reference Values

Negative or trace

Report Available

1 to 3 days

Day(s) Performed

Monday through Saturday

CPT Code Information

84376

Reject Due To

Urine and feces mixed
Feces collected in any preservative or fixative		 Reject

Useful For

Assisting in the differentiation between osmotic and nonosmotic diarrhea

 

Screening test for:

-Diarrhea from disaccharidase deficiencies, (eg, lactase deficiency)

-Monosaccharide malabsorption

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.

Specimen Retention Time

7 days

Forms

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