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HelpEpic Test Code LAB3868 Fat, Feces
Additional Codes
MML Code: FATF
LIS Code: LPTF
NY State Approved
YesPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Fat, FMethod Name
Nuclear Magnetic Resonance (NMR) Spectroscopy
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Fecal | Frozen (preferred) | 180 days | |
| Refrigerated | 180 days |
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 Type
FecalSpecimen Minimum Volume
See Specimen Required
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
Report Available
1 to 3 daysDay(s) Performed
Monday through Saturday
CPT Code Information
82710
Reject Due To
| Preservative, media, or charcoal | Reject |
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.
Clinical Information
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.
Interpretation
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:
(grams fat consumed - grams of fat excreted) x 100
CFA = grams of fat consumed
Cautions
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.
The use of charcoal as a marker is not recommended. If charcoal is used, please notify the laboratory.
Specimen Retention Time
7 daysForms
If not ordering electronically, complete, print, and send Gastroenterology and Hepatology Test Request (T728) with the specimen