Neutrophil Cytoplasmic Antibodies

Also known as: ANCA; MPO/PR3; c-ANCA; p-ANCA

In accordance with the revised 2017 international consensus on testing of ANCAs, and our own experience in Oxford, suggests that ANCA requests should be confined to patients with a high pre-test probability of small vessel vasculitis, if misleading 'false positives' in a range of non-vasculitic disorders are to be avoided.

Therefore, ANCA requests will be gated and only accepted from patients presenting with symptoms consistent with small vessel vasculitis as detailed below.

• Glomerulonephritis, especially rapidly progressing glomerulonephritis
• Pulmonary haemorrhage, especially pulmonary renal syndrome
• Acute pulmonary-renal syndrome
• Cutaneous vasculitis with systemic features
• Multiple lung nodules
• Chronic destructive disease of the upper airways
• Long-standing sinusitis or otitis
• Granulomatous nasopharyngeal lesions
• Subglottic tracheal stenoses
• Mononeuritis multiplex, or other peripheral neuropathy
• Retro-orbital mass
• Scleritis

To ensure optimal test usage, we will be accepting ANCA requests from the following specialities where most patients of the above spectrum will be seen:

• Rheumatology
• Renal/Nephrology
• Respiratory medicine
• Ear Nose and Throat
• Medical ophthalmology
• Dermatology

If you are concerned that your patient requires ANCA testing outside these specialties please supply relevant clinical details to ensure we do not screen out your request, and if still not accepted and you have a strong clinical suspicion for small vessel vasculitis then please do not hesitate to contact the laboratory:

Tel: 01865 225995

or any of the Immunology Medical team (via Switchboard), to discuss this further.

Requests not fulfilling the above criteria will not be processed and you will be notified on the report.

IgG antibodies directed against neutrophil enzymes systems are useful in the diagnosis and management of systemic necrotising vasculitis.

The main systemic necrotising vasculitides that are associated with a positive ANCA pattern are:

• Granulomatous Polyangiitis (GPA/Wegener's Granulomatosis)
• Microscopic Polyarteritis
• Rapidly Progressive Glomerulonephritis
• Churg-Strauss Syndrome.

Two major forms of pattern are seen: the cytoplasmic ANCA (cANCA) usually associated with autoantibodies against anti-proteinase 3 (PR3), and the perinuclear (pANCA) pattern generally associated with myeloperoxidase (MPO) autoantibodies.

Note 'false positives' may occur in diseases which may mimic systemic vasculitis e.g. infective endocarditis, tuberculosis, non-Hodgkin's lymphoma, acquired immune deficiency syndrome.

P-ANCA (of anti-MPO specificity) are found in up to 50 percent of patients with microscopic polyarteritis and pauci-immune glomerulonephritis, in addition to rheumatoid arthritis, SLE and ulcerative colitis.

Samples from known ANCA positive patients are tested for MPO or PR3 antibody levels, as appropriate. New ANCA positives are analysed for ANCA specificity and levels against both MPO and PR3.

Specimen requirements

Serum 1ml

Cost

Price on application

Laboratory turnaround time

4 days

Laboratory method

Indirect Immunofluorescnce

Reference range/units

ANCA

Positive or Negative with pattern and titre

MPO Antibody Levels

>5.0 IU/ml = Positive

3.5-5 IU/ml = Equivocal

<3.5 I​U/ml = Negative

PR3Antibody Levels

>3.0IU/ml = Positive

2-3.0 IU/ml = Equivocal

<2.0 I​U/ml = Negative

Associated tests

MPO/PR3

Sample stability

ANCA

1 month at 2-8ºC

MPO/PR3

2 months at 2-8ºC

Shipping and storage

UK and Ireland

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

International

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 immunologylab.enquiries@ouh.nhs.uk