ENA antibody

 

Alternative names, keywords

Extractable nuclear antigen, Ro, La, Sm, RNP, Jo-1, Scl70 antibody.

Samples required

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

Test indications

Diagnosis of connective tissue diseases.

Test information

The presence of specific antibodies directed against extractable nuclear antigens (ENAs) has predictive value for various CTDs. In this laboratory, the first-line test is ANA screen; if positive, we will automatically screen for common ENA antibodies and type if positive.

Screening and typing covers the following antibody specificities:

Ro52

Weak associations reported with inflammatory myositis, but found at high frequency in healthy individuals.

Ro60

Associated with SLE and Sjögrens. Small risk of fetal congenital heart block in pregnancy.

La

Associated with SLE and Sjögrens; usually found together with Ro.

SM

Associated with SLE.

RNP

Associated with SLE and mixed connective tissue disease (MCTD).

Scl70

Associated with primary systemic sclerosis.

Jo-1

Assocated with polymyositis.

Rare specificities such as Mi2 and PM-Scl antibody will not be picked up by this method.  Extended analysis is available on request where the clinical features are appropriate; please contact Dr Tarzi for discussion if needed.

Note that centromere antibody is picked up by indirect immunofluorescence in this laboratory.

Method: Phadia 250 ELIA

Reference range

Reported as positive, negative or equivocal.

Turnaround time

21 days.

Enquiries

Immunology