This study is about testing a new way to diagnose a condition called autoimmune pancreatitis (AIP). AIP can be hard to diagnose because it sometimes looks like other diseases. The study uses a system called the Odesa Criteria 2026 (OC26), which helps doctors decide if someone has AIP by looking at four different areas: morphology (the shape of the pancreas), serology (blood tests), clinical features (symptoms), and histology (tissue samples). Each area gives points, and the total score helps doctors make a diagnosis.

The study includes both looking back at past data (retrospective) and gathering new data (prospective). It checks how well the OC26 system works in real life by seeing how accurate it is compared to what doctors usually decide. They also check if different doctors agree when they use OC26.

• The study is observational, meaning no treatment is given.
• Participants must be 18 or older and suspected of having AIP.
• No compensation is mentioned for participating in this study.