Description
Antinuclear antibodies (ANA) are a group of autoantibodies produced by a person`s immune system when it fails to adequately distinguish between "self" and "nonself." The ANA test helps in detection of these autoantibodies in the blood.
ANA react with components of the body`s own healthy cells and cause signs and symptoms such as tissue and organ inflammation, joint and muscle pain, and fatigue. ANA specifically target substances found in the nucleus of a cell, hence the name "antinuclear." They probably do not damage living cells because they cannot access their nuclei. However, ANA can cause damage to tissue by reacting with nuclear substances when they are released from injured or dying cells.
The ANA test is one of the primary tests for helping to diagnose a suspected autoimmune disorder or rule out other conditions with similar signs and symptoms. The ANA test may be positive with several autoimmune disorders. Patients with the autoimmune disorder systemic lupus erythematosus (SLE) are almost always positive for ANA, but the percentage of patients with other autoimmune disorders who have positive ANA results varies. Also, a significant number of patients with a variety of other types of disorders (and even some heathy people) may be positive for ANA, especially at low levels.The antinuclear antibody (ANA) test is thus a primary test to help evaluate a person for autoimmune disorders that affect many tissues and organs throughout the body (systemic) and is most often used as one of the tests to help diagnose systemic lupus erythematosus (SLE). But a positive ANA test by itself does not diagnose any one particular disease.
Depending on a person`s signs and symptoms and the suspected disorder, ANA testing may be followed by doing additional tests for specific autoantibodies. Some of these tests are considered subsets of the ANA test and detect the presence of autoantibodies that target specific substances within cell nuclei, including anti-dsDNA, anti-centromere, anti-nucleolar, anti-histone and anti-RNA antibodies. An extractable nuclear antigen (ENA) panel (anti-RNP, anti-Sm, anti-SS-A, anti-SS-B, Scl-70, anti-Jo-1) may also be used in follow up to a positive ANA.The ANA test is ordered when someone shows signs and symptoms that a healthcare practitioner suspects are due to a systemic autoimmune disorder. People with autoimmune disorders can have a variety of symptoms that are vague and non-specific and that change over time, progressively worsen, or alternate between periods of flare ups and remissions.
This test is used to evaluate patients with suspected autoimmune rheumatic disease.The antinuclear antibody (ANA) test is used as a primary test to help evaluate a person for autoimmune disorders that affect many tissues and organs throughout the body (systemic) and is most often used as one of the tests to help diagnose systemic lupus erythematosus (SLE).
A positive ANA test result means that autoantibodies are present. In a person with signs and symptoms, this suggests the presence of an autoimmune disease, but further evaluation is required to assist in making a final diagnosis. ... Indirect fluorescent antibody (IFA)—the results are reported as a titer.ANA is reported as a "titer". Low titers are in the range of 1:40 to 1:60.Indirect fluorescent antibody (IFA)—the results are reported as a titer. Titers are expressed as ratios, which are obtained by diluting a portion of the blood sample with saline (salt water). A positive ANA test is of much more importance if you also have antibodies against the double-stranded form of DNA. The presence of ANA does not confirm a diagnosis of systemic lupus erythematosus (SLE).The lower the dilution ratio at which ANA is still detected, the higher the titer and the greater the amount of autoantibody present.Some infections, autoimmune hepatitis and primary biliary cirrhosis as well as other conditions mentioned above can give a positive result for the ANA test.
