What is Antinuclear Antibody Screen by Indirect Immunofluorescence?
Antinuclear antibodies are immunoglobulins directed against nuclear and cytoplasmic constituents. Indirect immunofluorescence on HEp-2 cells detects the full spectrum of ANA reactivity, including those to extractable nuclear antigens, dsDNA, centromere, and other intracellular targets. A positive screen reflects the presence of circulating autoantibodies but does not, on its own, establish a diagnosis — healthy individuals, particularly women and older adults, can have low-titre ANA without disease.