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Order Code LAB1385 Fat, Feces

Additional Codes

Mayo Test ID
FATF

Reporting Name

Fat, F

Useful For

Diagnosing fat malabsorption due to pancreatic or intestinal disorders

 

Monitoring effectiveness of enzyme supplementation in certain malabsorption disorders

 

This test is not useful for differentiating among pancreatic diseases.

Specimen Type

Fecal


Necessary Information


Length of collection period is required.



Specimen Required


Patient Preparation:

1. For 3 days prior to and during the collection period:

a. Patient should be on a fat-controlled diet (100-150 g fat per day).

b. No laxatives (particularly mineral oil and castor oil).

c. No synthetic fat substitutes (eg, Olestra) or fat-blocking nutritional supplements.

2. The use of diaper rash ointments will falsely elevate test results. Discontinue use during collection period.

3. Barium interferes with test procedure; a waiting period of 48 hours before stool collection analysis is recommended.

Supplies: Stool Containers - 24, 48, 72 Hour Kit (T291)

Container/Tube: Stool container complies with shipping requirements, do not use other containers.

Specimen Volume:

Preferred: Entire 48-hour or 72-hour collection

Acceptable: Entire 24-hour or a minimum of  5 g from a random collection

Collection Instructions:

1. All containers must be sent together.

2. The entire collection must contain at least 5 g of feces.

3. For a random collection, a minimum of 5 g (do not send entire collection) is required.

4. The number of containers sent should be indicated on the labels (1 of 4, for example).

Additional Information:

1. Patient can store sample at refrigerate temperature during collection period.

2. A separate order and collection should take place if stool bicarbonate, calcium, chloride, magnesium, osmolality, pH, potassium, sodium, or any microbiology testing is desired.


Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
Fecal Frozen (preferred) 180 days
  Refrigerated  180 days

Reject Due To

Preservative, media, or charcoal Reject

Reference Values

TIMED COLLECTION

≥18 years: 2-7 g fat/24 h

Reference values have not been established for patients who are younger than 18 years of age.

 

RANDOM COLLECTION

All ages: 0-19% fat

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Day(s) Performed

Monday through Saturday

Method Name

Nuclear Magnetic Resonance (NMR) Spectroscopy

CPT Code Information

82710

Method Description

After the well-homogenized stool sample is weighed and dried, it is rolled in Teflon and placed in a nuclear magnetic resonance spectrometer (NMR). The NMR determines the percent of fat in the sample. The percent is then converted to grams fat/24 hours excretion or percent fat of random sample.(Korpi-Steiner NL, Ward JN, Kumar V, McConnell JP. Comparative analysis of fecal fat quantitation via nuclear magnetic resonance spectroscopy [1H NMR] and gravimetry. Clin Chim Acta. 2009;400[1-2]:33-36)

Forms

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