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MPO/PR3 Anti-neutrophil cytoplasmic antibodies (ANCA)

Blood Sciences Test



Special Instructions

Minimum sample volume: 3 ml

Factors affecting results

None known

Reference Range

Myeloperoxidase (MPO) Antibodies

  • Negative: ≤5.0 IU/ml
  • Positive:   >5.0 IU/ml

Proteinase 3 (PR3) Antibodies

  • Negative: ≤3.0 IU/ml
  • Positive:   >3.0 IU/ml

Test Usage

ANCA are a characteristic finding in cases of ANCA-associated vasculitis (AAV), and are often requested as part of a “vasculitis screen.” Assays for MPO and PR3 autoantibodies are well established and in the context of a high-pretest probability of AAV they can be used as a first line test. These are more specific for ANCA-associated vasculitis than ANCA by immunofluorescence (which can be positive in a wide variety of clinical circumstances other than AAV). The diagnosis should be confirmed histologically wherever possible.

Please note that not all vasculitis is ANCA-associated and other causes should be considered.

Turnaround time

7 days


The Immunology laboratory provides this test routinely within normal working hours (09:00–17.30 Monday to Friday).

A limited weekend service is offered for clinically urgent ANCA (MPO/PR3 only) and GBM requests; this is normally provided on Saturday only, however a Sunday-only service is provided on bank holiday weekends. A named consultant is required for all urgent requests.

 Clinical Advice

Clinical advice is available from the Immunology Medical Team at Derriford Hospital. If you are concerned that your patient requires ANCA testing outside the recommended clinical indications, please contact the Immunology Clinical team on plh-tr.immunologylab@nhs.net to discuss this further.

T: 01752 431675


Specimen Labelling Procedure
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