From the Guidelines
Laboratory workup for autoimmune hepatitis should include liver function tests, complete blood count, and specific autoimmune markers, with the most important serological tests being antinuclear antibodies (ANA), anti-smooth muscle antibodies (ASMA), liver-kidney microsomal type 1 antibodies (anti-LKM1), and immunoglobulin G (IgG) levels, as recommended by the most recent guidelines 1. The diagnosis of autoimmune hepatitis (AIH) is based on a combination of clinical, laboratory, and histological findings. The laboratory workup should include:
- Liver function tests: ALT, AST, alkaline phosphatase, GGT, bilirubin
- Complete blood count
- Specific autoimmune markers:
- Antinuclear antibodies (ANA)
- Anti-smooth muscle antibodies (ASMA)
- Liver-kidney microsomal type 1 antibodies (anti-LKM1)
- Immunoglobulin G (IgG) levels Additional tests should include:
- Anti-soluble liver antigen (anti-SLA)
- Anti-liver cytosol type 1 (anti-LC1)
- Perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) Viral hepatitis markers (HBV, HCV) should be checked to exclude viral causes. A liver biopsy is often necessary for definitive diagnosis, showing interface hepatitis, lymphoplasmacytic infiltration, and other characteristic features. Patients should also be evaluated for concurrent autoimmune conditions like thyroid disease, celiac disease, and inflammatory bowel disease. The diagnosis of AIH is based on a scoring system that considers laboratory abnormalities, histological findings, and exclusion of other liver diseases, as outlined in the guidelines 1. Early diagnosis is crucial as prompt immunosuppressive therapy can prevent progression to cirrhosis and liver failure. The most recent guidelines recommend using the simplified diagnostic criteria for AIH, which include increased serum IgG levels, presence of ANA, SMA, or LKM-1, and compatible liver histology 1.
From the Research
Laboratory Workup for Autoimmune Hepatitis (AIH)
The laboratory workup for AIH involves several tests, including:
- Autoantibody detection, which is mandatory for AIH diagnosis and classification 2
- Serum globulin level tests, which are often elevated in AIH patients 3, 4
- Liver enzyme level tests, such as aspartate and alanine aminotransferase, which are often increased in AIH patients 5, 3
- Immunoglobulin G level tests, which are often increased in AIH patients 5, 3
Autoantibody Detection
Autoantibody detection is a crucial part of the laboratory workup for AIH, with different autoantibodies associated with different types of AIH:
- Type 1 AIH is characterized by seropositivity for smooth muscle and/or antinuclear antibodies 3, 4
- Type 2 AIH is characterized by positivity for liver kidney microsomal type 1 antibodies 3, 4
Diagnostic Scoring Systems
Diagnostic scoring systems, such as those established by the International Autoimmune Hepatitis Group (IAIHG), can support clinical judgment and serve as valuable tools in diagnosis and research 2, 6
- These scoring systems are based on several clinical, laboratory, and histological parameters 2
Histological Analysis
Histological analysis remains the cornerstone of AIH diagnosis, with liver biopsy essential to make the diagnosis 6
- Interface hepatitis with lymphoplasmacellular infiltrates on liver biopsy is a characteristic feature of AIH 4