Anti-Scl-70 test (anti-topoisomerase I antibody) is a blood test used to identify autoimmune antibodies primarily associated with systemic sclerosis (systemic scleroderma), especially the diffuse cutaneous type. These antibodies target the enzyme topoisomerase I, which plays a role in DNA unwinding and repair, and their presence is often considered a diagnostic and prognostic marker. The presence of Anti-Scl-70 is linked to a higher risk of internal organ involvement, such as lung fibrosis and kidney complications. This test is usually performed using immunoassay methods like ELISA or immunoblot and is useful in the differential diagnosis of systemic sclerosis from other autoimmune diseases like lupus or Sjögren’s syndrome. However, positive results should be interpreted alongside clinical symptoms (such as skin thickening and Raynaud’s phenomenon) and other tests, as these antibodies are rarely found in other diseases or healthy individuals. The presence of Anti-Scl-70 is particularly important for confirming diagnosis and assessing disease severity.
