Test Id : FATF
Fat, Feces
Useful For
Suggests clinical disorders or settings where the test may be helpful
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.
Method Name
A short description of the method used to perform the test
Nuclear Magnetic Resonance (NMR) Spectroscopy
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Fat, Feces, Random
Fecal Fat
Fecal Fat, Quantitative
Fecal Fat, Random
Lipids, Stool
Stool, Fat
Coefficient of Fat Absorption (CFA)
Fecal Fat, Timed
FATF
Specimen Type
Describes the specimen type validated for testing
Fecal
Necessary Information
Length of collection period is required.
ORDER QUESTIONS AND ANSWERS
| Question ID | Description | Answers |
|---|---|---|
| DUR2 | Duration |
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
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, chloride, magnesium, osmolality, phosphorus, pH, or any microbiology testing is desired.
Forms
If not ordering electronically, complete, print, and send Gastroenterology and Hepatology Test Request (T728)
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
See Specimen Required
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Preservative, media, or charcoal | Reject |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Fecal | Frozen (preferred) | 180 days | |
| Refrigerated | 180 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
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.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Total fecal lipids include glycerides, phospholipids, glycolipids, soaps, sterols, cholesteryl esters, and sphingolipids. Excess fecal fat in feces, (steatorrhea) is indicative of malabsorption disorders, such as pancreatic insufficiency or Whipple disease. Therefore, measurement of the fecal fats can be useful in establishing a diagnosis of such pancreatic diseases as cystic fibrosis, chronic pancreatitis, neoplasia, or stone obstruction and such intestinal diseases as Whipple disease, regional enteritis, tuberculous enteritis, gluten-induced enteropathy (also called celiac disease or sprue), and the atrophy of malnutrition.
Distinguishing free fatty acids from neutral fats, once thought to be helpful in the differential diagnosis of pancreatic disease, has fallen out of favor. Note that the composition of fats in the feces, normally predominately free fatty acids, can change significantly to predominately neutral fatty acids when the patient is on orlistat. This test does not distinguish between free and neutral fatty acids.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Timed Collection
> or =18 years: 2-7 g fat/24 h
Reference values have not been established for patients who are younger than 18 years.
Random Collection
All ages: 0-19% fat
Interpretation
Provides information to assist in interpretation of the test results
Excretion of more than 7 grams fat/24 hours, when on a diet of 100 to 150 g of fat, is suggestive of a malabsorption defect.
Abnormal results from a random specimen should be confirmed by submission of a timed collection.
Test values for timed fecal fat collections will be reported in terms of g/24 hours; the duration of the collection may be 24, 48, 72, or 96 hours. Test values for random fecal fat collections will be reported in terms of percent fat.
Coefficient of Fat Absorption (CFA) can be calculated as follows:
CFA = (grams of fat consumed - grams of fat excreted) x 100 / grams of fat consumed
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Proper patient preparation is critical (see Specimen Required). 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.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Hart PA, Conwell DL. Diagnosis of exocrine pancreatic insufficiency. Curr Treat Options Gastroenterol. 2015;13(3):347-353. doi:10.1007/s11938-015-0057-8
2. Sherwood RA, Walsham NE: Evaluation of fat absorption. In: Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:764
3. Erchinger F, Engjom T, Jurmy P, Tjora E, Gilja OH, Dimcevski G. Fecal fat analyses in chronic pancreatitis importance of fat ingestion before stool collection. PLoS One. 2017;12(1):e0169993. Published 2017 Jan 17. doi:10.1371/journal.pone.0169993
Method Description
Describes how the test is performed and provides a method-specific reference
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)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Saturday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
82710
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| FATF | Fat, F | 16142-2 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| STWT | Total Weight | 30078-0 |
| DUR2 | Duration | 13363-7 |
| PFAT | Percent Fat | 35745-9 |
| TFAT | Total Fecal Fat/24 Hr | 16142-2 |