Antinuclear Antibody

Other names: ANA; Fluorescent Antinuclear Antibody (FANA)

Antinuclear antibodies are a special group of antibodies, which are produced by the body when a patient has an autoimmune disorder, which causes the body to attack itself.

When is the test used?

The ANA test is used to screen for autoimmune diseases; in most cases, it is used to test for a specific condition known as systematic lupus erythematosus (also known as SLE).

The test is usually recommended for people who have symptoms of an autoimmune disorder; these include pain in the joints, fatigue and rashes (these may change in appearance over time).

How is the test performed?

The test is done by taking a sample of blood from a vein in the arm; the needle is usually inserted into a vein in the inside of the elbow. The needle is attached to a syringe; the sample will collect into the syringe and then it will be transferred into a special sample bottle after which the bottle will be labelled and sent off to the laboratory.

What do the test results show?

The ANA test is done using different assays (the ELISA test or indirect immunofluorescence microscopy); the results are recorded and interpreted using a titer (this is a measurement used in scientific laboratories; it is usually recorded as a ratio). If the test is positive, a certain type of fluorescence pattern will emerge in the results and the titer will be increased (a titer like 1:320 will indicate a positive result).

Different patterns are associated with different health conditions, as follows:

  • Homogenous pattern: associated with SLE and mixed connective tissue disease
  • Speckled pattern: associated with SLE, scleroderma, rheumatoid arthritis, mixed connective tissue disease and Sjogren’s syndrome
  • Nucleolar pattern: associated with polymyositis and scleroderma
  • Peripheral pattern: associated with SLE

Usually, doctors will order further tests to diagnose the exact autoimmune disease.

Specific Blood Tests

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