Liver function tests (LFTs) are the central test when investigating jaundice and often point towards the cause (Table 1).

Table 1 Liver function tests

Normal range notes
Alkaline phosphatase ALP 25-115U/L Considerably raised in extrahepatic and intrahepatic biliary disease
Transaminases AST 10-40U/LALT 5-40U/L Usually highly raised in hepatocellular disease
Gamma glutaryl transferese Male: <50 U/LFemale: <32 U/L Sensitive but not specific for alcohol intake, raised GGT and ALP suggest cholestasis

Other blood tests include:

  • Full blood count
    • Raised reticulocyte count and schistocytes on blood film indicate haemolysis
    • Coombs test will be positive
  • Amylase if raised may indicate pancreatitis
  • Hepatitis serology (for viral hepatitis)
  • Autoimmune markers
    • Markers such as anti-nuclear antibodies and anti-smooth muscle antibodies may indicate autoimmune disease
    • The majority of patients with PBC are positive for anti-mitochondrial antibody
    • Up to 85% of patients with PSC are positive with perinuclear staining anti-nuclear cytoplasmic antibody
  • Alpha 1 antitrypsin
    • Deficiency may proceed to liver cirrhosis
  • ¬†Copper/Ceruloplasmin
    • Deficiency may indicate Wilsons disease
  • Ferritin
    • Levels >1000 ng/ml and transferrin saturation >50% will indicate haemochromatosis