Anti-mitochondrial antibody (AMA) can be tested via indirect immunofluorescence. The auto-antigens of AMA have been identified as pyruvate dehydrogenase complex-E2 (PDC-E2), branched-chain 2-oxo acid dehydrogenase complex and 2-oxoglutaric acid dehydrogenase complex. The antibody to these antigens is known as AMA-M2. AMA-M2 is more specific to PBC than AMA, and the determination of its titer is feasible