Results help differentiate cholestasis from hepatocellular dysfunction (important because patients with cholestasis usually require imaging tests): Hepatocellular dysfunction: Marked aminotransferase elevation (> 500 U / L [8.35 microkat / L]) and moderate alkaline phosphatase elevation (< 3 times normal) Cholestasis: Moderate aminotransferase elevation (< 200 U / L [3.34 microkat / L]) and marked alkaline phosphatase elevation (> 3 times normal) Also, patients with hepatocellular dysfunction or cholestasis have dark urine due to bilirubinuria because conjugated bilirubin is excreted in urine; unconjugated bilirubin is not.