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Test ID NBLD0192 Reducing Substance, Feces

Reporting Name

Reducing Substance, F

Useful For

Assisting in the differentiation between osmotic and nonosmotic diarrhea


Screening test for:

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

-Monosaccharide malabsorption

Performing Laboratory

Mayo Medical 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 In Process


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

Analytic Time

1 day

Reject Due To








Specimens from timed collection (24, 48, 72 hour) or formed stool

Method Name

Benedict's Copper Reduction Reaction


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