Mitochondrial (M2) Antibody

M2 antibody is an autoantibody that targets mitochondrial enzymes, primarily used to detect primary biliary cholangitis (PBC), a chronic liver disease where the immune system attacks bile ducts. This test helps identify autoimmune liver conditions that may not show up on standard liver function tests.

When elevated: An elevated M2 antibody level typically indicates primary biliary cholangitis or another autoimmune liver disease. It suggests the immune system is attacking mitochondrial proteins in liver cells, which can lead to progressive bile duct damage and liver inflammation. When low: A negative or low M2 antibody level makes primary biliary cholangitis less likely, though it does not completely rule out the disease. Most people without autoimmune liver disease will have negative or undetectable M2 antibodies.

M2 antibody is not specifically relevant to athletic performance or training recovery. This test detects an autoimmune liver condition (primary biliary cholangitis) that requires medical evaluation regardless of activity level; athletes with unexplained fatigue, jaundice, or abnormal liver function should pursue this test on clinical grounds, not as a performance marker.