Extractable nuclear antigen Ab

Keywords: Extractable nuclear antigen antibody, ENA antibody


5 mL blood in plain tube.


Electrophoresis, ELISA , line blot.

Reference Interval:

Qualitative test


Performed when the ANA is positive to determine ANA specificities, some of which identify categories of disease with implications important for treatment and prognosis.

Also indicated when there is a high suspicion of connective tissue disease with negative ANA; antibodies to Ro (SS-A) may not be detected by ANA.


The presence of antibodies against extractable nuclear antigen is highly suggestive of systemic rheumatic disease.

Defined antigen specificities include:

RNP - mixed Connective tissue diseases;

Sm - highly specific for SLE;

Ro (SS-A) - subacute cutaneous lupus, associated with recurrent abortion, congenital heart block and Sjögren syndrome;

La (SS-B) - Sjögren syndrome;

Scl 70 - Scleroderma;

Jo-1 antibody - Myositis; and

PMSCL antibody – Polymyositis scleroderma overlap.


Tan EM et al. Clin Immunol Immunopath 1988; 47: 121-141.

Phan T et al. Clinical and Diagnostic Laboratory Immunology Jan 2002: 1 - 7.

Go Back

Page last updated:

Copyright © 2022 RCPA. All rights reserved.