SCL-70 Antibody, Serum is a diagnostic test used to determine the presence of SCL-70 antibodies in the blood. SCL-70 antibodies are a diagnostic marker for scleroderma or systemic sclerosis, an autoimmune disorder. An autoimmune disorder is a condition in which the immune system attacks its own body. Higher levels of SCL-70 antibody in the blood may indicate that a patient has scleroderma. However, the doctor may recommend additional tests like the antinuclear antibody test for confirmation.