Are there specific laboratory findings to establish the diagnosis?

Yes. The most specific laboratory derangements are found when measuring bile acids, specifically cholic acid and deoxycholic acid, which may be elevated more than 100 times (upper end of normal: 10 mmol/L). Liver transaminases (aspartate transaminase [AST], alanine transaminase [ALT]) may also be elevated, but ALT is thought to be the more sensitive marker, with an increase of 2 to 10 times the upper limit of normal. Bilirubin levels may be elevated, but total bilirubin levels do not often exceed 6 mg/dL.