What is the proper procedure for ordering liver panels?

How to Order Liver Panels

Initial investigation for potential liver disease should include bilirubin, albumin, ALT, ALP and GGT, together with a full blood count if not already performed within the previous 12 months. 1

Standard Liver Blood Test Panel Components

Initial Panel

• Bilirubin - measures liver's ability to process waste products 1
• Albumin - indicates synthetic function of the liver 1
• ALT (Alanine aminotransferase) - marker for hepatocellular injury 1
• ALP (Alkaline phosphatase) - associated with biliary disease 1, 2
• GGT (Gamma-glutamyltransferase) - increases sensitivity for detecting alcohol-related and non-alcoholic fatty liver disease 1
• Full blood count - particularly important to assess platelet count as thrombocytopenia may indicate advanced liver disease 1

Additional Testing Considerations

• AST (Aspartate aminotransferase) - while not recommended in the initial panel, calculating the AST:ALT ratio is valuable for assessing fibrosis risk 1
• PT/INR - should be considered when evaluating synthetic liver function 1

When to Order Liver Panels

Liver blood tests should be considered in the following scenarios:

• Suspected liver disease based on symptoms or risk factors 1
• Monitoring known liver conditions 1
• Screening high-risk populations (e.g., injecting drug users, migrants from high prevalence areas) 1
• Follow-up of abnormal liver blood tests 1

Follow-up Testing for Abnormal Results

When liver blood tests are abnormal, do not simply repeat the same panel. Instead:

1. Perform a standard liver aetiology screen including: 1

   • Abdominal ultrasound scan 1
   • Hepatitis B surface antigen 1
   • Hepatitis C antibody (with PCR follow-up if positive) 1
   • Autoimmune markers (anti-mitochondrial, anti-smooth muscle, antinuclear antibodies) 1
   • Serum immunoglobulins 1
   • Ferritin and transferrin saturation (for iron overload) 1

2. For children, the standard panel should be modified to include: 1

   • Anti-liver kidney microsomal antibody 1
   • Coeliac antibodies 1
   • Alpha-1-antitrypsin level 1
   • Caeruloplasmin (for children >3 years) 1

Pattern Recognition in Abnormal Results

• Hepatocellular pattern: Disproportionate elevation of ALT and AST compared to ALP 3
• Cholestatic pattern: Disproportionate elevation of ALP compared to ALT and AST 3
• AST:ALT ratio >1 suggests advanced fibrosis/cirrhosis 1

Important Considerations and Pitfalls

• Abnormal liver tests should prompt investigation regardless of the degree of abnormality 1
• 30-38% of initially abnormal liver tests may normalize on repeat testing, but this should not delay appropriate investigation 4
• A screening panel of tests is preferable to using a single test due to superior sensitivity and specificity 5
• GGT increases sensitivity but decreases specificity when added to the panel 1
• ALT and ALP alone can identify the majority of adults with liver disease, making them efficient choices when screening in primary care 2
• Normal liver tests do not exclude significant liver disease - both AST and ALT can be normal even in cirrhosis 1

Cost-Effective Approach

• A streamlined panel (ALT and ALP) may be sufficient for initial screening in primary care 2
• Consider "reflex" testing where additional tests (like AST) are automatically performed on the same sample if initial tests are abnormal 1
• For high-risk patients, consider simultaneous second-line testing rather than sequential testing 1