Diagnosing Autoimmune Hepatitis: Why a Positive Antibody Test Alone Isn't Enough

Autoimmune hepatitis (AIH) diagnosis requires a composite of clinical, biochemical, serological, and histological criteria (simplified IAIHG scoring).

Limitations of Serology Alone

• False positives: ANA, SMA, anti-LKM1 can occur in viral hepatitis, DILI, PBC, other autoimmune diseases, or even healthy people (low titers).
• False negatives: Up to 10–20% of AIH patients are seronegative at presentation.
• Nonspecific symptoms: Fatigue, arthralgia, abdominal discomfort overlap with many liver diseases.

Diagnostic Pillars

1. Biochemistry: Elevated AST/ALT, IgG (often >1.1× ULN).
2. Serology: ANA, SMA, anti-LKM1, anti-SLA/LP; exclude viral hepatitis (A, B, C, E), Wilson's, drug-induced.
3. Histology: Interface hepatitis, lymphoplasmacytic infiltration, rosettes—gold standard.
4. Exclusion of mimics: Alcohol, NAFLD, medications, viral, metabolic, genetic.
5. Response to immunosuppression: Supports diagnosis if criteria borderline.

Multidisciplinary Approach

Hepatologist, pathologist, radiologist collaboration ensures accurate diagnosis and avoids unnecessary lifelong immunosuppression.