What proportion of the general population is ANA-positive at a titer of 1:40? 1:160?
ANA titers of 1:40 are thought to be present in about 30% of the healthy population. The likelihood of a connective tissue disease rises with the ANA titer.
An ANA of 1:80 is seen in 13% of individuals, while an ANA of 1:160 is found in 5%. An ANA of 1:320 is seen in only 3.3% of healthy people.
Name four rheumatologic diagnoses that are associated with a positive ANA and four non-rheumatologic conditions that are associated with a positive ANA.
Estimates of the prevalence of ANA positivity in rheumatologic diseases:
- SLE: 98%
- Scleroderma: 85%
- Sjogren’s: 48%
- Rheumatoid arthritis: 41%
- Dermatomyositis and polymyositis: 61%
- Mixed connective tissue disease: 93%
- Drug-induced lupus: 100%
- Discoid lupus: 15%
- Pauciarticular juvenile idiopathic arthritis: 71%
Non-rheumatologic diseases associated with ANA-positivity:
- Grave’s disease or Hashimoto’s thyroiditis
- Hepatitis C
- Pimary biliary cirrhosis
- Autoimmune hepatitis
- Idiopathic pulmonary hypertension
- Subacute bacterial endocarditis
- Tuberculosis
- HIV
- Leukemia
- Lymphoma
Reference:
Tan EM, Feltkamp TE, Smolen JS et al. Range of antinuclear antibodies in “healthy” individuals. Arthritis Rheum 1997 Sep; 40(9): 1601-11
