ANA screen

 

Alternative names, keywords

Anti-nuclear antibody, ANF, CTD screen, connective tissue disease screen.

Samples required

Clotted blood (gold cap, 5 mL tube). Smaller tubes are available for paediatric samples.

Test indications

Investigation of possible connective tissue diseases such as SLE, Sjögrens, polymyositis, dermatomyositis and mixed connective tissue disease.

Test information

This immunoassay test format has replaced traditional indirect immunofluorescence (IIF) with Hep2 cells as the first-line test. The assay screens for antibodies directed against a mix of multiple ENA specificities and dsDNA; follow-on tests for individual ENA antibody profile, dsDNA antibody quantification and ANA (Hep2 indirect immunofluorescence are performed if equivocal or positive.

Compared to Hep2 IIF, the method is far more specific. It has excellent sensitivity for dsDNA and common ENA antibodies, and overall the predictive value for CTDs is comparable to ANA by Hep2 IIF. In certain situations (e.g. scleroderma) this method may be less sensitive. Please contact Dr Tarzi in case of queries.

Repeat analysis for known positives is not routinely required. For monitoring of known SLE patients, please request dsDNA antibody only.

Method: Phadia 250 ELIA

Reference range

Reported as positive, equivocal or negative.

Turnaround time

7 days.

Enquiries

Immunology