From the Guidelines
Laboratory evaluation of hepatitis should include liver function tests (LFTs), complete blood count (CBC), viral markers, and other specialized tests to determine the cause, severity, and appropriate treatment approach. The initial assessment typically involves LFTs, which include alanine aminotransferase (ALT) and aspartate aminotransferase (AST) - enzymes released when liver cells are damaged, as recommended by 1 and 1. Elevated levels indicate ongoing liver injury, with ALT being more liver-specific than AST. Alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) are cholestatic markers that rise when bile flow is impaired. Bilirubin levels help assess the liver's ability to process this waste product, with elevated levels causing jaundice. Albumin and prothrombin time evaluate the liver's synthetic function, with decreased albumin and prolonged clotting times suggesting advanced liver disease. Specific viral markers are crucial for identifying the cause: hepatitis A (anti-HAV IgM), hepatitis B (HBsAg, anti-HBc, HBeAg), and hepatitis C (anti-HCV, HCV RNA), as stated in 1 and 1. Additional tests may include complete blood count to assess for anemia or thrombocytopenia, and specialized tests for metabolic causes like iron studies for hemochromatosis, ceruloplasmin for Wilson's disease, and alpha-1 antitrypsin levels. Some key laboratory tests for evaluation of hepatitis include:
- Liver function tests (LFTs): ALT, AST, ALP, GGT, bilirubin
- Complete blood count (CBC)
- Viral markers: HBsAg, anti-HBc, HBeAg, anti-HCV, HCV RNA
- Autoimmune markers: anti-smooth muscle antibodies, anti-liver kidney microsomal antibodies, antinuclear antibodies
- Specialized tests: iron studies, ceruloplasmin, alpha-1 antitrypsin levels These tests collectively help determine the cause, severity, and appropriate treatment approach for hepatitis, as recommended by 1.
From the Research
Laboratory Tests for Hepatitis Evaluation
The following laboratory tests are used to evaluate hepatitis:
- Serum alanine aminotransferase (ALT) 2
- Serum aspartate aminotransferase (AST) 2
- Alkaline phosphatase 2
- Bilirubin (total, direct, and indirect) 2
- Hepatitis B surface antigen (HBsAg) 3, 4, 5
- Hepatitis B core antigen (HBcAg) 3
- Hepatitis C virus (HCV) antibody 3, 4, 5
- HCV RNA 3, 4, 5
Interpretation of Laboratory Results
The interpretation of laboratory results is crucial in the evaluation of hepatitis:
- Elevated ALT and AST levels indicate hepatocellular injury 2
- Elevated alkaline phosphatase levels indicate cholestatic injury 2
- Elevated bilirubin levels can occur in either hepatocellular or cholestatic diseases 2
- The presence of HBsAg and HCV antibody indicates hepatitis B and C infection, respectively 3, 4, 5
- The presence of HCV RNA indicates active hepatitis C infection 3, 4, 5
Diagnostic Algorithms
Diagnostic algorithms can be used to evaluate hepatitis:
- Testing for viral hepatitis A, B, and C, nonalcoholic fatty liver disease, and alcoholic liver disease 2
- Screening for hereditary hemochromatosis, autoimmune hepatitis, Wilson's disease, and alpha-1 antitrypsin deficiency 2
- Testing for primary biliary cholangitis and primary sclerosing cholangitis in cases of alkaline phosphatase elevation 2
- Liver biopsy may be considered when serologic testing and imaging fail to elucidate a diagnosis 2