How is dx of PBC done?

Labs (ALP and GGT increase 3-4 x normal, AST and ALT mild elevation (<3x), Bi normal early stages but may reach 20mg/dl, low serum albumin and prolonged prothrombin time (poor prognosis and advanced disease), 90% have + AMA (sens 98% spec 96%), RF (70%), Anti smooth muscle (66%), ANA (30%)..) Liver histology (Biopsy for final dx and exclusion of other causes, damage to epithelium in small bile ducts (initial), may be ductopenia (absence of interlobular bile ducts in more than 50% of portal tracts)