Autoantibody	Disease (frequency of autoantibody)	Cost ($)*	Comments
RF	Rheumatoid arthritis (80%), other connective tissue diseases (see Table 1)	15	Sensitive but not specific for rheumatoid arthritis; correlates with prognosis of disease severity (not disease activity)
ANA	Systemic lupus erythematosus (99%), drug-induced lupus (100%), other connective tissue diseases (see Table 2)	30	Sensitive but not specific for connective tissue diseases; correlates poorly with disease activity
Anti-dsDNA	Systemic lupus erythematosus (60%)	30	Specific but not sensitive for systemic lupus erythematosus; correlates with lupus nephritis and disease activity
Anti-ssDNA	Infrequent	200†	Nonspecific and of little clinical utility
Anti-histone	Drug-induced lupus (90%), systemic lupus erythematosus (50%)		Sensitive but not specific for drug-induced lupus
Anti-Sm	Systemic lupus erythematosus (20 to 30%)		Specific but not sensitive for systemic lupus erythematosus
Anti-U1 snRNP	Systemic lupus erythematosus (30 to 40%), mixed connective tissue disease (100%)		Associated with disease activity in systemic lupus erythematosus
Anti-Ro (anti-SS-A)	Sjögren's syndrome (75%), systemic lupus erythematosus (40%)		Associated with photosensitive skin rash, pulmonary disease and lymphopenia in systemic lupus erythematosus
Anti-La (anti-SS-B)	Sjögren's syndrome (40%), systemic lupus erythematosus (10 to 15%)		Associated with late-onset systemic lupus erythematosus, secondary Sjögren's syndrome and neonatal lupus syndrome
Anti-ribosome	Systemic lupus erythematosus (10 to 20%)	30	Highly specific but not sensitive for systemic lupus erythematosus; associated with lupus psychosis
Anti-centromere	Scleroderma (22 to 36%)	30	Associated with CREST syndrome and Raynaud's phenomenon
Anti-topoisomerase I (anti-Scl-70)	Scleroderma (22 to 40%)	40	Highly specific but not sensitive for scleroderma
Anti-Jo1	Polymyositis and dermatomyositis (30%)	40	Associated with pulmonary fibrosis and Raynaud's phenomenon
c-ANCA	Wegener's granulomatosis (>90%)	30	Highly specific and sensitive for Wegener's granulomatosis; correlates with disease activity
p-ANCA	Wegener's granulomatosis (10%), microscopic polyangiitis, glomerulonephritis	30	Sensitivity and specificity quite low in Wegener's granulomatosis