Bile Acids, Fractionated LCMS

Test ID: 

702791

CPT code:

82542

Synonyms:

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

Clinical 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.

Test 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 Type:

Serum (preferred) or plasma, frozen

Requested Volume: 

1 mL

Minimum Volume: 

0.3 mL

Container Type: 

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

Patient Preparation: 

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:

Rejection Criteria

Whole blood