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Antinuclear Antibody Test
ANA is an type of antibody that your body develops in some types of
autoimmune diseases. ANA are a unique group of antibodies that have the
ability to attack structures in the nucleus of cells. This is where they get
their name. Anti-nuclear means that the antibodies attack the nucleus of
your bodies cells. ANA is used in the diagnosis of SLE, Sjogren's syndrome,
scleroderma, polymyositis, rheumatoid arthritis, and mixed connective tissue
disease.
Purpose of
Antinuclear Antibody Test
The antinuclear
antibody test looks for a group of autoantibodies that attack substances
found in the center (nucleus) of all cells. It is useful as a screen for
many autoantibodies associated with diseases that affect the entire body
(systemic diseases).
This test is
particularly useful when diagnosing a person with symptoms of SLE, an
illness that affects many body organs and tissues. If the test is negative,
it is unlikely that the person has SLE; if the test is positive, more tests
are done to confirm whether the person has SLE or another related disease.
Other diseases, such as scleroderma
, Sjvgren's syndrome, Raynaud's disease, rheumatoid arthritis
, and autoimmune hepatitis, often have a positive test for antinuclear
antibodies.
What do the results of an Antinuclear Antibody
Test Mean.
Many people have low levels of ANA in their blood. This
tends to increase as we get older. It is possible to have higher levels of
ANA and not have an autoimmune disease. It is rare for this to happen and
when it does it is called a false positive. A normal ANA is anything that
shows up as less than 1:310 in a blood
titer. The higher
the concentration the lower ratios such as.
1:40 positive
1:80 positive
1:160 positive
--------------------------
1:320 negative
1:420 negative
What are the patterns of an Antinuclear Antibody Test.
ANA test results show up in patterns. So if you get test
results back from an ANA test it may show up as "Positive at 1:340 dilution
with a homogenous pattern". These patterns show up when views under a
powerful microscope. The common patterns of ANA are.
-
Homogenous (diffuse) - associated with SLE and mixed
connective tissue
disease
-
Speckled - associated with SLE, Sjogren's syndrome,
scleroderma, polymyositis,
rheumatoid
arthritis, and mixed
connective tissue disease
-
Nucleolar - associated with scleroderma and polymyositis
-
Outline pattern (peripheral) -associated with SLE
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