IgG4/IgG RNA ratio does not accurately discriminate IgG4-related disease from pancreatobiliary cancer

IgG4-related disease (IgG4-RD) of the biliary tract and pancreas is often difficult to distinguish from pancreatobiliary cancer. The blood IgG4/IgG RNA ratio has been reported to discriminate IgG4-RD from primary sclerosing cholangitis/pancreatobiliary cancer with high accuracy. This study aimed to prospectively assess the diagnostic accuracy of the blood IgG4/IgG RNA ratio for distinguishing IgG4-RD from cancer in patients with a suspected...