What is the most common blood test for systemic lupus erythematosus?

The most common blood test for SLE is the antinuclear antibodies (ANA) test, which is positive in the majority of people with SLE. However, this test can be positive for a number of reasons outside of SLE, such as when someone has a different autoimmune disease (like rheumatoid arthritis) or even when someone is completely healthy and has no disease at all (considered a false positive). This is one reason why it is important to work with a trusted medical provider for an SLE diagnosis.^[1] Other antibody blood tests that are often used in the diagnosis of lupus include anti-dsDNA (anti-double-stranded DNA), anti-Sm (anti-Smith), and antiphospholipid antibodies.