Nuclear Antibodies (ANA)

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Assay

Anti-nuclear antibodies (ANA)

Key Words

Anti-Nuclear antibody (ANA) screen , ANA (CTD)

Specimen Collection

Serum (brown)

Turnaround time

5 days (10 days for HEp-2)

Test indications

These are a heterogeneous group of antibodies that bind to nuclear antigens.  ANA negative SLE is extremely rare. However the test is not specific for SLE as  anti nuclear antibodies can occur in other conditions e.g. rheumatoid arthritis, systemic sclerosis, chronic active hepatitis, juvenile arthritis, Sjögren’s syndrome, MCTD, fibrosing alveolitis, systemic infections and can be induced by drugs such as hydralazine.  Low titre ANAs can also be found in the serum of many healthy elderly people.

Minimum retesting interval

Requests made within 60 days of a previous request on a patient are intervened.

Methodology

Frontline screen: Fluoroenzyme immunoassay

The antibodies screened for in this assay include: dsDNA, U1RNP (RNP70, A, C), Ro52, Ro60, La (SS-B), Scl-70, Centromere B, Jo-1, Fibrillarin, RNA Pol III, Ribosomal-P, PM-Scl, PCNA, Mi-2 proteins and Sm proteins.

 

Confirmationary testing:ENA screen, dsDNA, ENA profile by enzyme immunoassay (EIA) and HEp-2 by indirect immunofluorescence (IFA).

Interferences

No known methodological interferences

Reference Range

Negative : <0.7

Equivocal : 0.7-1.0

Positive : >1.0

Analytical error

Contact Immunology laboratory (x8454)

Reference change value

N/A

Other information

Click here for ANA Assay Flow Chart