From the Guidelines
Primary Biliary Cholangitis (PBC) can be diagnosed with confidence in adult patients with otherwise unexplained elevation of alkaline phosphatase (AP) and presence of antimitochondrial antibodies (AMA) (P1:40) and/or AMA type M2, without the need for a liver biopsy, as stated in the EASL clinical practice guidelines 1. The diagnostic criteria for PBC typically involve a combination of laboratory tests and imaging studies. Key findings include:
- Elevated alkaline phosphatase (AP) and gamma-glutamyl transferase (GGT) indicating cholestasis
- Presence of antimitochondrial antibodies (AMA) at titers of 1:40 or higher, which are positive in about 95% of PBC patients
- Elevated immunoglobulin M (IgM) levels and mild to moderate elevations in aminotransferases (AST, ALT) Imaging studies such as ultrasound, CT, or MRI are performed to exclude other causes of biliary obstruction. In cases where AMA is negative but PBC is still suspected, testing for PBC-specific antinuclear antibodies (ANA) like anti-sp100 and anti-gp210 can be helpful, as suggested by the EASL guidelines 1. A liver biopsy may be performed in ambiguous cases to confirm the diagnosis, showing characteristic bile duct destruction, granulomatous inflammation, and progressive fibrosis. According to current guidelines, PBC can be diagnosed when two of three criteria are met: elevated ALP, positive AMA, or compatible liver histology, as stated in the EASL clinical practice guidelines 1. Early diagnosis is crucial as treatment with ursodeoxycholic acid (UDCA) can slow disease progression and improve outcomes. It is essential to note that a detailed history and physical examination are also vital in the diagnosis of PBC, as emphasized in the EASL guidelines 1. Ultrasound is the first-line non-invasive imaging procedure to differentiate intra- from extrahepatic cholestasis, and testing for serum antimitochondrial antibodies (AMA) is mandatory in adults with chronic intrahepatic cholestasis, as recommended by the EASL guidelines 1.
From the Research
Diagnostic Criteria for Primary Biliary Cholangitis (PBC)
The diagnostic criteria for PBC include:
- Presence of antimitochondrial antibodies (AMA) or specific antinuclear antibodies 2
- Cholestatic biochemical profile 2
- Chronic elevation of alkaline phosphatase and the presence of anti-mitochondrial antibodies or other specific antinuclear antibodies (i.e. anti-gp210 and anti-sp100) 3
- Liver biopsy is recommended only in selected cases, such as patients with isolated AMA and normal alkaline phosphatase levels 2
- Baseline serum immunoglobulin M (IgM) >0.773 × upper limit of normal (ULN) and age >42 years may suggest a diagnosis of PBC in patients with seropositive AMA but normal ALP 4
Key Diagnostic Features
- Antimitochondrial antibodies (AMA) are highly specific for PBC 5
- Cholestatic liver tests, such as elevated alkaline phosphatase, are commonly seen in PBC patients 5, 2
- Liver biopsy can provide relevant information for risk stratification and prediction of treatment response 2