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Immunology Laboratory

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ENA Screen

Extractable nuclear antigens form part of the investigation process of many rheumatological disorders. The antigens within this screen are as follows:

  • U1-snRNP
    Antibodies appear in both SLE and mixed connective tissue disease (MCTD). In MCTD the presence of U1-snRNP antibodies is required for diagnosis, whereas they occur in only 30-40% of SLE patients.
  • RNP-70
    High titres of RNP-70 may be more specific for MCTD, reported to occur less frequently in SLE.
  • Sm
    Antibodies are a highly specific but comparatively insensitive clinical marker for SLE.
  • Anti-Ro60 (SS-A)
    Significant in the clinical diagnosis of SLE (prevalence 40-50%) and Sjogren's syndrome (prevalence 60-75%). Have been reported to occur in association with certain disease subsets such as; subacute cutaneous LE, neonatal lupus or vasculitis in Sjogren's syndrome.
  • Anti-Ro52
  • Anti-La (SS-B)
    Serological hallmark of Sjogren's syndrome, however a small proportion of patients do remain negative. Also present in mothers of newborns with neonatal lupus.
  • Anti-Scl-70
    Characteristic and specific for scleroderma (particularly the diffuse form; frequency up to 70%).
  • Jo-1
    Jo-1 antibodies can be found as markers in dermatomyositis/polymyositis (prevalence 25%), but also in patients with polymyositis overlap syndrome. They are associated with interstitial pneumonitis (in the context of myositis) more frequent in adults than juvenile myositis. Patients with Jo-1 antibodies tend to have a severe form of the disease with a tendency to relapse and a poorer prognosis.
  • CENP
    See Centromere antibodies above.

NB In keeping with current evidence-based guidelines, antibodies to DNA and ENA antigens will not be performed on sera that are negative for ANA.

Specimen requirements

Serum 1ml


Price on application

Laboratory turnaround time

5 days

Laboratory method

EliA automated Enzyme Immunoassay

Reference range/units

Reported as Positive or Negative

Associated tests

ANA and dsDNA antibodies

Sample stability

2 months at 2-8ÂșC

Shipping and storage

UK and Ireland

Ambient temperature and first class post. Hays DX users please enquire via email below.


Ambient temperature if courier will deliver within 72 hours otherwise consider refrigerated transport. Freezing is not a requirement.

Ensure delivery Monday to Friday 09:00 - 17:30.

Further information and contact details

For further information, email

Last reviewed:06 October 2023