Hi,
Thank you for your query. I can understand your concerns.
Antinuclear Antibody (ANA)-Primary disease association (sensitivity, specificity):SLE(>95 %,low).often used as screening test; a negative test virtually excludes SLE; a positive test while non-specific, increases post-test probability of SLE. Titer does not correlate with disease activity.
Other disease association with positive ANA:rheumatoid arthritis(30-50 %),
discoid lupus,scleroderma(60 % ),drug-induced lupus(100 %),Sjogren's syndrome(80 %),miscellaneous inflammatory disorders.
Do test for Anti-double- stranded DNA/anti-ds-DNA (sensitivity, specificity):SLE ( 60-70 %,high )& Anti-Smith antibody/anti-Sm (sensitivity, specificity):SLE (30-40 %,high ).
The specificity of Anti-smith & Anti-double stranded DNA for Systemic lupus erythemtosus (SLE )ranges from 55 -100%.
Regards
Dr. T.K. Biswas M.D.
Mumbai