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Antibodies to Extractable Nuclear Antigens

Item Value
Approval req'd? No
Available Stat? No
Test code AENA
Performed by Immunology
In House Availability Wednesday (day shift)
Method EIA
Container type Gold top
Amount to Collect 1 mL blood
Sample type Serum
Preferred volume 0.5 mL serum
Processing notes Freeze serum at -20C
Units Units
Normal range For both anti-SM and anti-SM/RNP:
Negative < 20 Units
Weak Positive 20-39 Units
Moderate Positive 40-80 Units
Strong Positive > 80 Units
Synonyms ENA; anti-SM; anti-RNP; anti-ENA; anti-smith; RNP antibody; Sm antibody; Smith antibody; Sm/RNP
Turn around times 2-9 days
Additional information Systemic lupus erythematosus (SLE) is characterized by the presence of autoantibodies. One class of autoantibodies is directed against extractable nuclear antigens, often producing a speckled pattern on ANA screening.

Antibodies to Sm are present in approximately 40% of patients with SLE and are considered to be highly specific markers for this disease.

The RNP antigen is closely associated with the Sm antigen and is designated the Sm/RNP complex. Anti-RNP antibodies are found in a variety of rheumatic diseases including scleroderma, rheumatoid arthritis, discoid lupus, polymyositis, and Sjogren's syndrome.

Testing is performed against the Sm antigen alone and against the Sm/RNP complex (testing for RNP alone is not available)

Weak positive results may not have clinical significance. Clinical correlation is advised. Repeat testing may be considered, if clinical indicated
LOINC code 43182-5
Last Updated 4/21/2014 9:18:49 AM
Entry Number 338
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