High levels of<unk>  (in general, above 20 IU/mL, 1:40, or over the 95th percentile; there is some variation among labs) occur in<unk>  arthritis (present in 80%) and Sjögren's syndrome (present in 70%). The higher the level of<unk>  the greater the probability of destructive articular disease. It is also found in Epstein–Barr virus or Parvovirus infection and in 5 to 10% of healthy persons, especially the elderly. There is an association between<unk>  and more persistently active synovitis, more joint damage, greater eventual disability and arthritis. Other than in<unk>  arthritis,<unk>  may also be elevated in: * Systemic lupus erythematosus (SLE) *Juvenile Idiopathic Arthritis * Sjögren syndrome * Interstitial pulmonary fibrosis * Hepatitis B and C, chronic liver disease, and chronic hepatitis * Essential mixed cryoglobulinemia * Primary biliary cirrhosis * Infectious mononucleosis and any chronic viral infection * Bacterial endocarditis * Leprosy * Sarcoidosis * Tuberculosis * Syphilis * Visceral leishmaniasis * Malaria * Leukemia * Dermatomyositis * Systemic sclerosis * After vaccination/transfusion in normal individuals
Rheumatoid factor
C-ANCA
Antisperm antibodies
Anti–citrullinated protein antibody
Anti-neutrophil cytoplasmic antibody
Microantibody
Anti-nuclear antibody
ANA-12