Epic Test Code LAB101011 Bile Acids, Bowel Dysfunction, 48 Hour, Feces
Additional Codes
MML:BA48F
Useful For
Aids in evaluation of patients suspected of having irritable bowel syndrome-diarrhea symptoms due to bile acid malabsorption
Reporting Name
Bile Acids, Bowel Dysfunc, 48 Hr, FSpecimen Type
FecalOrdering Guidance
This test is for evaluation of bowel dysfunction or confirmatory testing for bile acid malabsorption using a 48-hour fecal collection.
For evaluation of hepatobiliary dysfunction, order BILEA / Bile Acids, Total, Serum.
For evaluation of patients treated with urso or cholate, order BAFS / Bile Acids, Fractionated and Total, Serum.
For evaluation of inborn errors of metabolism, order BAIPD / Bile Acids for Peroxisomal Disorders, Serum.
Specimen Required
Patient Preparation:
1. The patient should be on a fat-controlled diet (100-150 g fat per day) for 3 days before and during the collection period.
2. Patient should not use:
 a. Antibiotics for 7 days before or during specimen collection
 b. Statins for 5 days before or during specimen collection
 c. Laxatives (particularly mineral oil and castor oil) for 3 days before or during specimen collection.
 d. Bile acid sequestrants for 24 hours before or during specimen collection
 e. Synthetic fat substitutes (eg, Olestra) or fat-blocking nutritional supplements for 24 hours before or during the specimen collection
3. If the patient has used barium, it is recommended to wait at least 48 hours before collecting the specimen.
Supplies: Stool Containers - 24, 48, 72 Hour Kit (T291)
Collection Container/Tube: Stool container that complies with shipping requirements
Specimen Volume: Entire 48-hour collection
Collection Instructions:
1. Do not use other containers.
2. Freeze immediately.
3. All containers must be sent together.
4. The entire collection must contain at least 5 g of feces.
5. The number of containers sent should be indicated on the labels (1 of 4, for example).
Additional Information:
1. The patient may store specimen at refrigerate temperature during the collection period, but it must be frozen immediately after completion.
2. If additional tests are ordered, aliquot and separate sample prior to freezing to allow 1 container per test.
Specimen Minimum Volume
5 g
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Fecal | Frozen | 30 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
Bile acids are natural products of cholesterol synthesis that aid in the emulsification and absorption of dietary fats in the small intestine. The majority of bile acids are reabsorbed in the ileum of the healthy individual, with only 5% excreted in feces.(1) Primary bile acids cholic acid (CA) and chenodeoxycholic acid (CDCA) are deconjugated and dehydroxylated via intestinal bacteria into secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA), respectively.(2) The sum of CA, CDCA, DCA, LCA, and ursodeoxycholic acid (UDCA) compose the majority of bile acids in the feces. Impaired absorption of bile acids in the terminal ileum leads to excess bile acids in the colon that can cause diarrhea from chloride and water secretion; a condition called bile acid malabsorption (BAM).
Irritable bowel syndrome (IBS) is a nonspecific multifactorial disorder involving the large intestine. IBS is characterized by cramping, bloating, diarrhea, and constipation and classified as either IBS-D (diarrhea) or IBS-C (constipation) by the Rome III criteria.(3) Up to 50% of IBS-D patients have accelerated colonic transit time; the mechanism of IBS-D pathophysiology is varied with more than 25% having BAM.(1,4)
Several methods have been developed for detection of BAM, but are not widely available in clinical practice.(5) Therefore, patients are often placed on trials of bile acids sequestrants to determine if symptoms improve.
Quantitation of fecal bile acids aids in screening for IBS-D and identification of patients with chronic diarrhea who may benefit from bile acid sequestrant therapy.
Reference Values
≥ to 18 years:
Sum of cholic acid and chenodeoxycholic acid ≤9.7%
Total bile acids ≤2619 mcmoles/48 h
Reference values have not been established for patients who are younger than 18 years of age
Interpretation
Elevated total fecal bile acid or percent cholic acid plus chenodeoxycholic acid is consistent with the diagnosis of bile acid malabsorption.
Pharmacological treatment with bile acid sequestrants has been shown to improve symptoms in some patients.
Cautions
Bile acids are not stable in stool. Stool samples must be kept frozen immediately after collection.
Supportive Data
Bile acid (BA) malabsorption is suspected when total BA is greater than 2337 mcmol/48h, or primary BA (% cholic acid plus chenodeoxycholic acid) is greater than 10%, or total BA is greater than 1000 mcmol/48h + primary BA is greater or equal to 4%.(1)
Specimen Retention Time
7 daysPerforming Laboratory
Mayo Clinic Laboratories in RochesterCPT Code Information
82542
NY State Approved
YesMethod Name
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Special Instructions
Forms
If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.
Testing Algorithm
For information see Bile Acid-Associated Tests Ordering Guide
Day(s) Performed
Wednesday