From the Guidelines
If you suspect Intrahepatic Cholestasis of Pregnancy (ICP), you should order total serum bile acids as the primary diagnostic test, along with liver function tests including ALT, AST, GGT, alkaline phosphatase, and bilirubin (total and direct) 1.
Diagnostic Tests for ICP
The following tests are recommended:
- Total serum bile acids: the most sensitive and specific test for ICP, with levels typically elevated above 10 μmol/L and often exceeding 40 μmol/L in affected women
- Liver transaminases (ALT and AST): elevated in 60-80% of ICP cases, sometimes reaching 2-10 times the upper limit of normal
- Alkaline phosphatase: often elevated but has limited diagnostic value as it naturally increases during pregnancy
- Bilirubin (total and direct): typically normal or mildly elevated, with clinical jaundice occurring in only about 10-15% of cases
- GGT: may help distinguish ICP from other liver disorders
Rationale for Test Selection
These tests are recommended based on the latest guidelines from the American Gastroenterological Association (AGA) and the European Association for the Study of the Liver (EASL) 1. The AGA guidelines recommend measuring serum bile acid levels and liver transaminases in patients with suspected ICP, while the EASL guidelines provide an algorithm for the management of ICP based on serum bile acid levels and other factors.
Additional Tests to Consider
Additional tests to exclude other liver diseases might include:
- Hepatitis serology
- Autoimmune markers
- Ultrasound imaging of the liver and biliary tract These tests can help distinguish ICP from other liver disorders and guide further management. Regular monitoring of serum bile acid levels and liver function tests is also recommended to assess disease progression and guide treatment decisions 1.
From the Research
Liver Labs for Intrahepatic Cholestasis of Pregnancy
To diagnose and manage Intrahepatic Cholestasis of Pregnancy (ICP), several liver labs should be performed, including:
- Total bile acids (TBA) levels: Elevated levels of TBA are a key diagnostic criterion for ICP, and monitoring these levels throughout pregnancy is crucial, as concentrations above 40 μmol/L define severe ICP and are associated with an increased risk of fetal complications 2, 3.
- Alanine aminotransferase (ALT) levels: ALT levels are often elevated in ICP patients, and monitoring these levels can help diagnose and manage the condition 2, 3, 4.
- Aspartate aminotransferase (AST) levels: AST levels may also be elevated in ICP patients, and monitoring these levels can provide additional information for diagnosis and management 3, 4.
Rationale for Liver Labs
The rationale for performing these liver labs is to:
- Confirm the diagnosis of ICP, which is characterized by pruritus, elevated bile acid levels, and abnormal liver function tests 2, 3, 4, 5, 6.
- Monitor the severity of ICP and adjust treatment accordingly, as elevated bile acid levels are associated with an increased risk of fetal complications 2, 3.
- Evaluate the effectiveness of treatment, such as ursodeoxycholic acid, which can improve maternal pruritus symptoms and biochemical tests 2, 3, 5.