What labs are used to diagnose and monitor autoimmune hepatitis?

From the Guidelines

The diagnosis and monitoring of autoimmune hepatitis rely on a combination of laboratory tests, including liver function tests, autoantibody testing, immunoglobulin levels, complete blood count, and viral hepatitis markers, as recommended by the most recent guidelines 1. The initial workup for autoimmune hepatitis typically includes:

• Liver function tests such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), and bilirubin levels to assess liver damage and function.
• Autoantibody testing, which is crucial and includes:
  • Antinuclear antibodies (ANA)
  • Anti-smooth muscle antibodies (ASMA)
  • Liver-kidney microsomal type 1 antibodies (anti-LKM1)
  • Soluble liver antigen/liver pancreas antigen (SLA/LP) antibodies
• Immunoglobulin levels, particularly IgG, which are often elevated in autoimmune hepatitis.
• Complete blood count (CBC) to reveal anemia or thrombocytopenia.
• Viral hepatitis markers (hepatitis A, B, C) to exclude viral causes. For monitoring disease activity and treatment response, regular assessment of liver enzymes (ALT, AST) and IgG levels is recommended every 3-6 months, with autoantibody titers checked periodically, as suggested by the latest clinical practice guidelines 1. These tests help clinicians evaluate inflammation, assess treatment efficacy, and detect potential disease flares early, allowing for timely adjustment of immunosuppressive therapy.

From the Research

Diagnostic Labs for Autoimmune Hepatitis

The diagnosis of autoimmune hepatitis (AIH) involves a combination of clinical, laboratory, and histological findings. The following labs are used to diagnose and monitor AIH:

• Liver function tests, including transaminase levels 2, 3
• Immunoglobulin G (IgG) levels 2, 3
• Autoantibody tests, including:
  • Antinuclear antibodies (ANA) 2, 4, 5
  • Anti-smooth muscle antibodies (SMA) 2, 4, 5
  • Anti-liver kidney microsomal antibody type 1 (LKM-1) 2, 4, 5
  • Anti-liver cytosol type 1 (LC1) 2, 4, 5
  • Anti-soluble liver antigen (SLA) antibodies 2, 4, 5
  • Perinuclear anti-nuclear neutrophil antibody (p-ANNA) 2, 5
• Histological examination of liver tissue to demonstrate interface hepatitis and periportal necrosis 2, 3

Interpretation of Lab Results

The interpretation of lab results is crucial in the diagnosis of AIH. The following points should be considered:

• A positive test for autoantibodies does not necessarily confirm the diagnosis of AIH, as these antibodies can be present in other conditions as well 6
• The presence of multiple autoantibodies can increase the diagnostic accuracy of AIH 4, 5
• The titer of autoantibodies can be important in the diagnosis of AIH, with a titer of 1/40 or higher being considered significant in adults 5
• The pattern of staining on indirect immunofluorescence can be helpful in distinguishing between different types of autoantibodies 5

Monitoring of Autoimmune Hepatitis

The monitoring of AIH involves regular laboratory tests to assess the response to treatment and to detect any potential complications. The following labs are used to monitor AIH:

• Liver function tests, including transaminase levels 2, 3
• Immunoglobulin G (IgG) levels 2, 3
• Autoantibody tests, including ANA, SMA, LKM-1, LC1, and SLA 2, 4, 5
• Regular histological examination of liver tissue to assess the degree of inflammation and fibrosis 2, 3