Lab Dept:

Urine/Stool

Test Name:

REDUCING SUBSTANCES, STOOL

General Information

Lab Order Codes:

RSUB

Synonyms:

Stool Reducing Substances; Fecal Reducing Substances

CPT Codes:

81002 – Urinalysis, by dipstick or tablet reagent; non-automated, without microscopy

Test Includes:

Test for fecal reducing substance as an indication of disaccharidase (sucrase, lactase) deficiency. Reducing substances detected include glucose, fructose, lactose, galactose, and pentose.

Logistics

Lab Testing Sections:

Microbiology

Phone Numbers:

Minneapolis:

Saint Paul:

612-813-5866

651-220-6555

Test Availability:

Daily, 24 hours

Turnaround Time:

4 hours

Special Instructions:

Specimen site and date/time of collection are required for specimen processing.

Specimen

Specimen Type:

Random stool

Container:

Plastic, leakproof container

Volume:

2 grams or 2 mL stool

Collection:

● Collect stool in a clean, dry bedpan or on a newspaper over the toilet. Transfer specimen to a plastic, leakproof container. Do not overfill or contaminate the outside of the container.
● Pediatric patients with severe diarrhea may use a U-bag collection system. Place the bag over the anal area in an attempt to retrieve the specimen before it soaks into the diaper. The diaper can also be reversed with the plastic side toward the skin to prevent the specimen from soaking into the diaper. Transfer specimen into a plastic, leakproof container.

Transport/Storage:

Specimen must be received in the laboratory within 1 hour of collection. Delay may cause falsely low results. Freeze specimen if testing is delayed. Do not send specimen through the pneumatic tube system.

Sample Rejection:

No diapers accepted. Improperly labeled specimen; specimen contaminated with urine and/or water; leaking container; insufficient volume; specimen containing interfering substances such as castor oil, bismuth, Metamucil®, barium, Vaseline®, or other cream contaminants. If an unacceptable specimen is received, the physician or patient’s nurse will be notified and another specimen will be requested before the specimen is discarded.

Interpretive

Reference Range:

≤0.25% gm/dL

Negative/Normal

0.25% - 0.5% gm/dL

Borderline

>0.5% gm/dL

Positive/Abnormal

Limitations:

Bacterial fermentation may give falsely low results if specimen is not analyzed within 1 hour. In the neonatal period, high Clinitest® results may be observed.

Methodology:

Clinitest®

References:

Cook, JH, and M Pezzlo (1992) Specimen receipt and accessioning. Section 1. Aerobic bacteriology, 1.2.1-4. In HD Isenberg (ed) Clinical Microbiology Procedures Handbook. American Society for Microbiology, Washington DC

Miller, J Michael (1999) A Guide To Specimen Management in Clinical Microbiology, American Society for Microbiology, Washington DC

Miller, J Michael, and HT Holmes (1999) Specimen Collection, Transport, and Storage In PR Murray et al, (ed), Manual of Clinical Microbiology, 7th edition, American Society for Microbiology, Washington DC, pp 33-104