Fat, Stool (Sendout)

single page view

General Information

Lab Name
Stool Fat
Lab Code
RSFAT
Epic Name
Stool Fat (Sendout)
External Test Id
FATF
Description

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.

Patient Preparation:

  • For 3 days prior to and during the collection period:
    • Patient should be on a fat-controlled diet (100-150 g fat per day).
    • No laxatives (particularly mineral oil and castor oil).
    • No synthetic fat substitutes (eg, Olestra) or fat-blocking nutritional supplements.
  • The use of diaper rash ointments will falsely elevate test results. Discontinue use during collection period.
  • Barium interferes with test procedure; a waiting period of 48 hours before stool collection analysis is recommended.
Synonyms
Fat Feces, Fecal Fat, Stool Lipids, T291
Components
Code Name
RSTLWT Weight, STL
RSTINV Interval, STL
RSFATP Percentage Fat, STL
RSFATT Total Fat, STL

Interpretation

Method

Nuclear Magnetic Resonance (NMR) Spectroscopy

Reference Range
See individual components
Ref. Range Notes

Reference Values:

Timed Collection: > or =18 years: 2-7 g fat/24 h*
Random Collection: All ages: 0-19% fat

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

Interferences and Limitations

Cautions: Proper patient preparation is critical. Failure to adhere to a fat-controlled diet or to exclude other oils or oil substitutes from the diet may make interpretation difficult.

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

The use of charcoal as a marker is not recommended. If charcoal is used, please notify the laboratory.

Ordering & Collection

Specimen Type
Stool, Feces
Collection

Timed Collection: 48 or 72 hour (preferred) stool collection in Mayo containers (Supply T291).
Also Acceptable: 24 hour or random collection (see below).

  • Obtain stool collection containers (Mayo Kit T291) from HMC Specimen Processing Services (GWH-47) or UW-MT Specimen Processing Services (NW-220). Outside Clients: Contact Client Support Services at (206) 520-4600 or commserv@uw.edu.
  • Mayo recommends one kit (2 containers) for every 24 hours of collection.
  • Label all containers with name and MRN or date of birth, and container number (1 of 4, 2 of 4, etc.).
  • Refrigerate sample(s) during collection. (Samples can also be frozen during collection, but should not be left at ambient temperature.)
  • Length of collection period is required for processing.

Random collection:

  • Collect a minimum of 5 g stool in a screw-cap, preservative-free collection container.
  • Refrigerate sample if delivery to the lab is delayed.
Handling Instructions

Outside Laboratories:

Timed Stool:

  • Freeze stool at -20°C in Mayo collection containers. Transport on dry ice. The collection interval must be included on the requisition.
  • Each container must be marked indicating the collection order and total number of containers used in the collection (e.g. 1 of 5, 2 of 5, 3 of 5 etc.).
  • Do not split or aliquot timed stool samples.
  • Samples submitted in other containers will be rejected.

Random Stool: Freeze 5 g of stool in preservative-free container at -20°C. This sample cannot be shared; submit separate samples for each stool test ordered.

Stability: Frozen (preferred): 180 days; Refrigerated: 180 days, Ambient: Unacceptable.

Reject Due To: Preservative, media, or charcoal.

Quantity
Requested: Timed: Entire stool collection. Random: 5 g stool.
Minimum: Timed: Entire stool collection. Random: 5 g stool.

Processing

Receiving Instructions

Timed Stool: Freeze stool at -20°C in Mayo collection containers. Collection period must be indicated on the requisition.

  • Each container must be marked indicating the collection order and total number of containers used in the collection (e.g. 1 of 5, 2 of 5, 3 of 5 etc.).
  • Do not split or aliquot timed stool samples.
  • If sample arrives in a paint can, contact the Lab Medicine Resident on-call for further instruction.

Random Stool: Freeze 5 g of stool in preservative-free container at -20°C.

  • NOTE (Random Stools only): If a single stool specimen is received for multiple tests, samples may be sent to Micro to be split prior to freezing. Include CID labels and directions for splitting (including minimum volumes). If there is insufficient sample, contact provider to prioritize testing.

Sendouts:

  • Order Mayo Test: FATF
  • Interfaced: Yes [Interface: 601; Worksheet: MAFZ]
  • For timed collections:
    • Send all containers together and ensure that the order and number of collection is indicated on the labels (1 of 5, etc.).
    • Include the collection interval (24, 48, 72 hr) in the MayoAccess order.
    • Copy the Mayo Batch Sheet and include with each sample.

Stability: Frozen (preferred): 180 days; Refrigerated: 180 days, Ambient: Unacceptable*.

  • *Samples may remain ambient for a short window but should be frozen upon receipt at the lab. Contact Mayo Clinic Laboratories at (800) 533-1710 for questions about sample acceptibility.

Reject Due To: Preservative, media, or charcoal.

Misc Sendout

Performance

Lab Department
Sendouts Mayo Lab (FZ)(MAFZ)
Frequency
Performed: Monday through Saturday. Reported: 1-3 days from sample receipt at Mayo Clinic Labs.
Available STAT?
No
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Billing & Coding

CPT Codes
82710
LOINC
18719-5
Interfaced Order Code
UOW2301