Jo-1

The Jo-1 test is used to detect antibodies against the JO-1 protein, which plays a role in muscle and tissue function. Jo-1 antibody is a myositis-specific autoantibody most commonly found in patients with idiopathic inflammatory myopathies (IIM). This test is primarily used to help diagnose IIM, particularly Dermatomyositis (DM) and Polymyositis (PM). It can be considered a specific marker of IIM, predominantly found in these conditions. The test is also associated with Interstitial Lung Disease (ILD), Raynaud phenomenon, arthritis, and mechanic's hands. A positive result suggests the presence of anti-synthetase syndrome (a rare autoimmune disease that affects multiple systems of the body) or a higher risk of myositis (muscle inflammation). A negative result means the antibodies are not detected, but it does not completely rule out the diagnosis of idiopathic inflammatory myositis. Further tests may be needed for a definitive diagnosis.