Antinuclear
antibody (ANA) test a marker of the autoimmune process
that is positive with a variety of autoimmune diseases. It may be
positive in
- Systemic lupus erythematosus,
- Sjögren's syndrome,
- Rheumatoid arthritis,
- Autoimmune hepatitis, etc
Methods of detection of
ANA
- Indirect Immuno
flourescence- gold standard (
80%-sensitivity;specificity-90-97%)
- ELISA (
99%-sensitivity;specificity-36-94%)
- Immunodiffusion
(outchterlony)
- CIEP
(Counterimmuno-electrophoresis)
- Multiple immunobead
assay
Principle
- An indirect
immunofluorescence technique isutilized where
patient samples and appropriatecontrols are incubated with the
substrate slides.
- The unreacted antibodies are washed off and anappropriate
fluorescence labeled conjugate isapplied.
- Unbound conjugate is washed off, and slides areviewed with a
fluorescence microscope.
- Positive
samples produce apple-greenfluorescence.