This test measures the concentration of antinuclear antibodies (ANA) in the blood, aiding in the diagnosis of autoimmune disorders such as lupus, scleroderma, and Sjögren’s syndrome. A higher ANA level may indicate active disease, while lower levels suggest remission or mild activity. It provides more detailed information than a qualitative test and helps monitor disease progression and treatment response. Clinical correlation with symptoms and other autoimmune markers is essential for accurate diagnosis.