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Test Code 7AC4 7AC4, Bile Acid Synthesis, Serum


Specimen Required


Patient Preparation:

1. Patient must be fasting for at least 12 hours; fasting morning specimen is preferred.

2. Patient should not be taking bile acid sequestrants or statins.

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL


Useful For

Screening for bile acid malabsorption in patients with irritable bowel syndrome-diarrhea (IBS-D)

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Stable Isotope Dilution Analysis

Reporting Name

7AC4, Bile Acid Synthesis, S

Specimen Type

Serum

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Frozen (preferred) 90 days
  Refrigerated  72 hours
  Ambient  24 hours

Reject Due To

Hemolysis

Mild OK; Gross OK

Lipemia

Mild OK; Gross OK

Icterus

Mild OK; Gross OK

Other

NA

Reference Values

≥18 years: 2.5-63.2 ng/mL

Reference values have not been established for patients who are <18 years of age.

Interpretation

In patients with irritable bowel syndrome-diarrhea (IBS-D), elevated 7alpha-hydroxy-4-cholesten-3-one (7AC4) is consistent with bile acid diarrhea (BAD). A result of 17.6 ng/mL or greater is 83% sensitive and 53% specific for BAD. In these cases, a confirmatory 48-hour fecal bile acid test could be considered. A result above 52.5 ng/mL is 40% sensitive and 85% specific for BAD.

 

Interpretation in patients with chronic diarrhea:

 

----------------------------------17.6----------------------------------------------------52.5--------------------------

   BAM unlikely                                 Indeterminate                                   BAM likely

   (consider other                       (consider confirmatory                          (consider bile acid

    conditions)                            fecal bile acids test or trial                        sequestrant therapy)

                                                  of bile acid sequestrant)

Day(s) and Time(s) Performed

Wednesday; 8 a.m.

Analytic Time

2 days

Specimen Retention Time

14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
7AC4 7AC4, Bile Acid Synthesis, S In Process

 

Result ID Test Result Name Result LOINC Value
65504 7AC4, Bile Acid Synthesis, S In Process