Bile Acids

CPT: 82239
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Test Details

Synonyms

  • Glyco and Taurochenodeoxycholic Acid

Use

Evaluate the enterohepatic cycle consisting of the biliary system, intestine, portal circulation, and hepatocytes

Methodology

Enzymatic

Reference Interval

See table.

Male (Age)

Range (μmol/L)

0 to 1 y

Not established

2 to 12 y

5.6−27.6

>12 y

3.8−20.9

Female (Age)

Range (μmol/L)

0 to 1 y

Not established

2 to 5 y

7.5−40.4

6 to 50 y

4.7−24.5

>50 y

4.1−23.9

Pregnant Female (Age)

Range (μmol/L)

15 to 45 y

3.7−14.5

Additional Information

The concentration of bile acids in serum is elevated in patients with many structural liver diseases, due to the inability of the liver to extract bile acids efficiently from portal blood. Metabolic liver diseases such as Gilbert disease, Crigler-Najjar syndrome, or Dubin-Johnson syndrome do not appear to cause elevated bile acid concentrations. Bile acid levels may be altered even when other liver function tests are normal and may serve as a sensitive and specific indicator of liver disease.

Intrahepatic cholestasis of pregnancy (ICP) is a temporary condition caused by maternal liver dysfunction during pregnancy. It is characterized by intense generalized pruritus (itchiness) which usually begins in the third trimester. ICP is also known as cholestatic jaundice of pregnancy, cholestatic hepatosis, icterus gravidarum, and obstetric cholestasis.

There are several laboratory tests which can be done to confirm a diagnosis of cholestasis of pregnancy, including bile acids. Maternal blood levels of bile salts are often at least three times the normal level in ICP; however, the levels may be 10 to 100 times normal. Blood tests can also reveal increased levels of other liver enzymes that indicate general liver dysfunction, such as ALT, AST, and alkaline phosphatase. While ALT/AST levels may be normal or slightly elevated, alkaline phosphatase levels are almost always higher than normal (though this may be due, in part, to the alkaline phosphatase added to the mother's blood from the placenta). However, if the liver enzymes are extremely elevated, other causes, such as viral hepatitis, should be considered. In the absence of bile acid tests, elevated ALT, AST and/or alkaline phosphatase levels in the setting of intense pruritus are generally adequate to diagnose cholestasis of pregnancy.

Though it may cause extreme discomfort, cholestasis of pregnancy is regarded as benign to the mother; however, it has been widely established that ICP poses a significant increased risk to the fetus and is associated with an increased incidence of stillbirth. Fetal death in ICP is a real risk and the primary objective of treatment is to make certain that the baby is born before stillbirth occurs. While the fetal death rate for untreated patients is around 10%, studies in which patients are induced before term have found fetal mortality rate to be 0% to 2%. The danger from ICP is eliminated when the child is safely delivered and labor is induced when the fetus' lungs are mature, regardless of any other test results.

After delivery, the symptoms in the mother usually decrease within 48 hours of delivery and disappear completely within four weeks postpartum. Cholestasis of pregnancy does not cause permanent liver impairment to the mother and the liver returns to normal function, once the baby is delivered.

Specimen Requirements

Specimen

Serum, frozen

Volume

1 mL

Minimum Volume

0.2 mL

Container

Red-top tube or gel-barrier tube

Patient Preparation

Patient should be fasting; however, a two-hour postprandial level has been used by various physicians in order to evaluate hepatic function after the gallbladder has been completely emptied (ie, challenge the liver with a high level of bile acids in the portal circulation).

Collection

Transfer serum to a plastic transport tube before freezing. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Storage Instructions

Freeze.

Stability Requirements

Temperature

Period

Room temperature

1 day

Refrigerated

3 days

Frozen

7 days

Freeze/thaw cycles

Stable x3

Causes for Rejection

Specimen not transported and received refrigerated; plasma sample

Clinical Information

References

Block E, Rutner H. Efficacy of postprandial bile acid levels as diagnostic tool for hepatobiliary disease. Clin Chem. 1979; 25:1081, 31st National Meeting of the American Association for Clinical Chemistry July 15-20, 1979, New Orleans, La.
Korman MG, Hofmann AF, Summerskill WH. Assessment of activity in chronic liver disease: Serum bile acids compared with conventional tests and histology. N Engl J Med. 1974 Jun 20; 290(25):1399-1402. 4133590
Mashige F, Tanaka N, Maki A, Kamei S, Yamanaka M. Direct spectrophotometry of total bile acids in serum. Clin Chem. 1981 Aug; 27(8):1352-1356.
Skrede S, Solberg HE, Blomhoff JP, Gjone E. Bile acids measured in serum during fasting as a test for liver disease. Clin Chem. 1978 Jul; 24(7):1095-1099.657487

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
010330 Bile Acids 14628-2 010330 Bile Acids umol/L 14628-2

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