Bile Acids, Fractionated and Total, LC/MS-MS

CPT: 82542
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Test Details

Use

This assay uses LC/MS-MS to quantify the free acid, glycine-conjugate and taurine-conjugate forms of cholic acid, chenodeoxycholic acid, deoxycholic acid, and ursodeoxycholic acid. Bile acids may be measured to investigate obstructive cholestasis in pregnancy.1 In addition, bile acids are required for cholesterol absorption, fat-soluble vitamin absorption, and to provide resistance to overgrowth of intestinal bacteria.1 Bile acid levels may be reduced or elevated due to various genetic defects.

Methodology

High-pressure liquid chromatography/tandem mass spectrometry (HPLC/MS-MS)

Additional Information

Bile acids are formed in the liver from cholesterol, stored and concentrated in the gallbladder, and excreted into the intestines in response to food. The liver synthesizes cholesterol into two primary bile acids, cholic acid and chenodeoxycholic acid. The primary bile acids are converted by intestinal bacteria to the secondary bile acids, deoxycholic acid and lithocholic acid. A fraction of chenodeoxycholic acid is also transformed into the tertiary bile acid, ursodeoxycholic acid.

Specimen Requirements

Specimen

Serum (preferred) or plasma, frozen

Volume

1 mL

Minimum Volume

0.3 mL (Note: This volume does not allow for repeat testing.)

Container

Red-top tube, gel-barrier tube, lavender-top (EDTA) tube, or green-top (sodium heparin) tube

Patient Preparation

Patient should be fasting.

Collection

Serum/plasma must be separated from cells within two hours of venipuncture. Transfer serum/plasma to a plastic transport tube before freezing.

Storage Instructions

Refrigerate or freeze.

Stability Requirements

Temperature

Period

Room temperature

1 day

Refrigerated

3 days

Frozen

14 days

Freeze/thaw cycles

Stable x6

Causes for Rejection

Whole blood

Clinical Information

Footnotes

1. Monte MJ, Marin JJ, Antelo A, Vazquez-Tato J. Bile acids: Chemistry, physiology, and pathophysiology. World J Gastroenterol. 2009; 15(7):804-816.19230041

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
503640 Bile Acids, Fractionated LCMS 503642 Ursodeoxycholic Acids umol/L 55159-8
503640 Bile Acids, Fractionated LCMS 503643 Cholic Acids umol/L 30518-5
503640 Bile Acids, Fractionated LCMS 503644 Chenodeoxycholic Acids umol/L 30519-3
503640 Bile Acids, Fractionated LCMS 503645 Deoxycholic Acids umol/L 30520-1
503640 Bile Acids, Fractionated LCMS 503641 Total Bile Acids umol/L 14628-2
503640 Bile Acids, Fractionated LCMS 503608 Bile Acids, Fractionated LCMS N/A

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