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Test ID: BAFS Bile Acids, Fractionated and Total, Serum

Ordering Guidance

This test is useful in diagnosing intrahepatic cholestasis of pregnancy and does not support the assessment of either peroxisomal biogenesis disorders or inborn errors of bile acid metabolism.


For diagnostic testing for peroxisomal biogenesis disorders, order BAIPD / Bile Acids for Peroxisomal Disorders, Serum.

Specimen Required

Patient Preparation: Patient must be fasting for 12 to 14 hours.

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


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

Useful For

Measuring tauro- and glycol-conjugated and unconjugated bile acid constituents in serum specimens


Monitoring patients receiving bile acid therapy, such as cholic acid, deoxycholic acid, or ursodeoxycholic acid


Aiding in the evaluation of liver function; evaluation of liver function changes before the formation of more advanced clinical signs of illness such as icterus


Determining hepatic dysfunction as a result of chemical and environmental injury


Indicating hepatic histological improvement in chronic hepatitis C patients responding to interferon treatment


Indicating intrahepatic cholestasis of pregnancy


This assay is not useful for the diagnosis of peroxisomal biogenesis disorders or inborn errors of bile acid metabolism.

Testing Algorithm

For more information see Bile Acid-Associated Tests Ordering Guide

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Reporting Name

Bile Acids, Fractionated and Tot, S

Specimen Type


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 90 days
  Ambient  90 days
  Frozen  90 days

Clinical Information

Bile acids are formed in the liver from cholesterol, conjugated primarily to glycine and taurine, stored and concentrated in the gallbladder, and secreted into the intestine after the ingestion of a meal. In the intestinal lumen, the bile acids serve to emulsify ingested fats and thereby promote digestion. During the absorptive phase of digestion, approximately 90% of the bile acids are reabsorbed.


The efficiency of the hepatic clearance of bile acids from portal blood maintains serum concentrations at low levels in normal persons. An elevated fasting level, due to impaired hepatic clearance, is a sensitive indicator of liver disease. Following meals, serum bile acid levels have been shown to increase only slightly in normal persons, but markedly in patients with various liver diseases, including cirrhosis, hepatitis, cholestasis, portal-vein thrombosis, Budd-Chiari syndrome, cholangitis, Wilson disease, and hemochromatosis. No increase in bile acids will be noted in patients with intestinal malabsorption. Metabolic hepatic disorders involving organic anions (eg, Gilbert disease, Crigler-Najjar syndrome, and Dubin-Johnson syndrome) do not cause abnormal serum bile acid concentrations.

Reference Values

Total cholic acid: ≤5.00 nmol/mL

Total chenodeoxycholic acid: ≤6.00 nmol/mL

Total deoxycholic acid: ≤6.00 nmol/mL

Total ursodeoxycholic acid: ≤2.00 nmol/mL

Total bile acids: ≤19.00 nmol/mL


Total bile acids are metabolized in the liver and can serve as a marker for normal liver function. Increases in serum bile acids are seen in patients with acute hepatitis, chronic hepatitis, liver sclerosis, liver cancer, and intrahepatic cholestasis of pregnancy.

Clinical Reference

1. Marschall HU. Management of intrahepatic cholestasis of pregnancy. Expert Rev Gastroenterol Hepatol. 2015;9(10):1273-1279

2. Ducroq DH, Morton MS, Shadi N, et al. Analysis of serum bile acids by isotope dilution-mass spectrometry to assess the performance of routine total bile acid methods. Ann Clin Biochem. 2010;47(Pt 6):535-540

3. Piechota J, Jelski W. Intrahepatic cholestasis in pregnancy: Review of the literature. J Clin Med. 2020;9(5):1361. doi:10.3390/jcm9051361

Day(s) Performed

Monday through Friday

Report Available

3 to 5 days

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 US Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
BAFS Bile Acids, Fractionated and Tot, S 43130-4


Result ID Test Result Name Result LOINC Value
35796 Total Cholic acid 30518-5
35797 Total Chenodeoxycholic acid 30519-3
35798 Total Deoxycholic acid 30520-1
35799 Total Ursodeoxycholic acid 55159-8
35800 Total bile acids 14628-2
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