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Test ID: FBAC Bile Acids, Urine

Method Name

Fast Atom Bombardment-Mass Spectrometry (FAB-MS)

Reporting Name

Bile Acids, Urine

Specimen Type


Specimen Required

Collection Container: Plastic urine container

Specimen Volume: 5-25 mL

Collection Instructions:

  1. Collect 5-25 mL random urine without preservative.
  2. Ship frozen in a plastic container.


NOTE: Submit with specimen:

1. Clinical history/Preliminary diagnosis


-Because URSO can mask detection of bile acid synthetic defects it is preferable for patients to be off Urso or Actigall for 5 days before sample collection.


-If possible, send Urine & Serum (ZW166 - Bile Acids Serum, referral lab code 9001004). Urine is analyzed for all patients - if Urine shows evidence of a metabolic abnormality, Serum will be tested. Urine and serum must be ordered separately as they are 2 separate tests with separate charges.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred)
  Ambient  48 hours
  Refrigerated  48 hours

Day(s) Performed


Report Available

7 to 30 days

Test Classification

This test was developed and its performance characteristics were determined and validated by the Clinical Mass Spectrometry Laboratory at Cincinnati Childrens Hospital Medical Center. It has not been cleared or approved by the U. S. Food and Drug Administration. This laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA 88) as qualified to perform high-complexity laboratory testing.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
FBAC Bile Acids, Urine 49254-6


Result ID Test Result Name Result LOINC Value
FBAC Bile Acids, Urine 49254-6

Clinical Information

Diagnostic testing in pediatric and adult patients presenting with conditions of cholestatic liver disease, neurological disease, or fat-soluble vitamin malabsorption of unknown etiology. Urine FAB-MS analysis provides a rapid and cost-effective means of diagnosing the most common of the genetic defects in the metabolism of cholesterol to the primary bile acids. Mass spectrometry testing may be used to monitor the biochemical response to primary bile acid therapy and to help in decisions on dose adjustments, where compliance should lead to a reduction in levels of atypical bile acids.


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

Mayo Clinic Laboratories | Gastroenterology Catalog Additional Information: