From the Guidelines
A liver screen should include initial investigation with bilirubin, albumin, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and γ-glutamyltransferase (GGT), along with a full blood count if not already performed within the previous 12 months, as recommended by the guidelines on the management of abnormal liver blood tests 1.
Initial Investigation
The initial investigation for potential liver disease should include a series of blood tests to assess liver function and detect potential liver diseases.
- Bilirubin levels to check for jaundice
- Albumin levels to assess liver protein synthesis
- Liver enzymes (ALT, ALP, GGT) to evaluate liver damage
- Full blood count to rule out other conditions
Additional Tests
Additional tests may be included in the liver screen depending on clinical suspicion, such as:
- Hepatitis viral markers to check for hepatitis B and C
- Autoimmune antibodies to evaluate for autoimmune liver diseases
- Iron studies to assess for iron overload
- Alpha-1 antitrypsin levels to evaluate for alpha-1 antitrypsin deficiency
Importance of Liver Screening
Regular liver screening is particularly important for those with chronic conditions like diabetes or those taking medications that can affect liver function, as early recognition of liver disease and appropriate treatment can prevent progression to end-stage liver disease 1.
Liver Aetiology Screen
A standard liver aetiology screen should include abdominal ultrasound scan (USS), hepatitis B surface antigen, hepatitis C antibody, anti-mitochondrial antibody, anti-smooth muscle antibody, antinuclear antibody, serum immunoglobulins, simultaneous serum ferritin and transferrin saturation, as recommended by the guidelines on the management of abnormal liver blood tests 1.
From the Research
Liver Screen Tests
- The most common liver chemistries ordered are serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, and bilirubin 2
- These tests should be termed liver chemistries or liver tests, and are used to assess abnormal liver chemistries on a daily basis 2
Interpretation of Liver Screen Results
- Hepatocellular injury is defined as disproportionate elevation of AST and ALT levels compared with alkaline phosphatase levels 2
- Cholestatic injury is defined as disproportionate elevation of alkaline phosphatase level as compared with AST and ALT levels 2
- Elevated conjugated bilirubin implies hepatocellular disease or cholestasis 2
Evaluation of Abnormal Liver Chemistries
- The evaluation of hepatocellular injury includes testing for viral hepatitis A, B, and C, assessment for nonalcoholic fatty liver disease and alcoholic liver disease, screening for hereditary hemochromatosis, autoimmune hepatitis, Wilson's disease, and alpha-1 antitrypsin deficiency 2
- A history of prescribed and over-the-counter medicines should be sought 2
- For the evaluation of an alkaline phosphatase elevation determined to be of hepatic origin, testing for primary biliary cholangitis and primary sclerosing cholangitis should be undertaken 2
Role of Protein C and Antithrombin III in Liver Disease
- Protein C and antithrombin III can be considered as markers of different stages of chronic liver disease 3
- Protein C is more sensitive than antithrombin III as a marker of hepatocellular damage 3
- Antithrombin III and protein C showed a significant negative correlation with (ALT, AST, PT, PTT, INR), and a positive correlation with albumin 3