A diagnosis is NEVER made based on antibodies.
Antibodies directed against a variety of nuclear antigens, including nucleic acids, histones and components of the centromere.
Antibodies are sensitive markers for SLE (over 95%), but specificity is low - are found in 3-5% of healthy people and with other diseases. If negative, the need to persue other testing is not necessary.
Can also be positive in lymphoproliferative diseaae, chronic infections, a number of drugs, and other things.
Conditions associated with a positive ANA include
from a human tumor cell line are placed on a slide and coated with
serial dilutions of the patient’s serum. Using fluorescein-labeled
anti-human IgG to detect the bound autoantibodies, the technician
reports the pattern of staining.
Staining Patterns are important, but have largely been replaced by extractable nuclear antigens
A positive titer is > 1/100.
Immunoassay techniques allow detection of antibodies against cellular antigens.