A young woman presents to the clinic for evaluation of a facial rash, as well as symptoms of arthralgias and fatigue. The symptoms started a few months ago and are not resolving. On physical examination, the rash on her face is erythematous and raised, the heart and lungs are normal, and the wrists are swollen and tender on palpation. Laboratory evaluation is only significant for mild thrombocytopenia (90,000/mL). Which of the following is the most appropriate initial autoantibody test?
High-Yield Explanation
ANA is the most important diagnostic autoantibodies in patients being evaluated for SLE. It is rare to have ANA negative SLE. The other antibodies can occur in SLE but not as sensitive for the diagnosis as ANA. Anti-dsDNA and anti-SM are specific for SLE but not sensitive.