ANA (Anti-Nuclear Antibody) test is one of the most prescribed tests in Rheumatic Diseases, especially Rheumatoid Arthritis.
It is used to evaluate the probability of Systemic Rheumatic Disease, Autoimmune Collagen Tissue Disease.
What is the ANA Test ?
ANA can be called briefly autoantibodies against intra-nuclear structures.
All antigenic structures within the nucleus can be the target of ANA antibodies. ELISA or IFA technique can be used for ANA antibody screening.
Hep-2 cell lysate is used as antigen in screening studies using ELISA technique. To increase sensitivity, dsDNA, histone, SS-A (Ro), SS-B (La), Smith, RNP, Scl-70, Jo-1 and centromer antigens were added to this lysate.
If the results of the study with ELISA are found positive, further evaluations are carried out in order to determine which Antigenic structures against which antibodies are formed.
Today, many centers prefer the IFA technique where Human Epithelioma Type 2 (HEp-2) cells are used as the substrate.
When Hep-2 Cells are used as substrates, around 30 Nuclear or Cytoplasmic Patterns formed by about 100 autoantibodies can be obtained.
What Does it Mean to Test Positive for ANA ?
In studies performed using the Hep-2 substrate in various clinical situations, the rates of achieving a “Positive” result are given in a table.
In chronic infections, it is not uncommon and positive results can be found at low titer. However, it should be noted that autoantibodies may become Positive months or even years before the disease occurs.
Systemic Lupus Erythematosus
Discoid Lupus Erythematosus
Lupus Erythematosus induced by drugs
Mixed Connective Tissue Disease (MCTD)
CREST syndrome (Calcinosis, Raynaud phenomenon, Esophageal dysmotility, Sclerodactyly and Telangiectasia)
It is very high in systemic and organ-specific autoimmune diseases such as dermatomyositis.
ANA positivity can be seen in 3-4 % of healthy people.
With the advancement of age, pseudo-ANA positivity in low titer is common. Over 80 years of age, this rate can reach 50 %.
How is ANA Test Done ?
A tube taken from the arm is studied from the blood.
Hunger is not necessary.
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