Most specific test for SLE

Ans.(c) Anti- smith antibodyTest Description* ANA Screening test has sensitivity 95% not diagnostic without clinical features* Anti-dsDNA Antibody: High specificity, sensitivity only 70% and levels are variable based on disease activity* Anti-Sm antibody: Most specific antibody for SLE* AntiSSA (Ro) or Anti-SSB (La) Present in 15% of patients with SLE and other connective tissue disease such as Sjogren syndrome* Lupus anticoagulant* Direct Russell viper venom test to screen for inhibitors in the clotting cascade in antiphospholipid antibody syndrome* Direct Coombs test* Anti-histone : Drug-induced lupus (e.g with procainamide or hydralazine)