Pathology tests database

Sample and container requirements

Serum

Minimum volume required

4 ml Blood

Special requirements

None

Patient preparation

None

Sample viability

Store at 4oC

Turnaround time

4 days

Reference range

Negative

Clinical guidance

Some indications: Screening test for small vessel vasculitis. Seen particularly in Wegener's granulomatosis (WG), microscopic polyangitis (MPA) and its renal limited variant (pauci-immune crescentic glomerulonephritis) and Churg-Strauss syndrome If this test is required urgently please contact the Duty Immunologist via bleep 2119 during the normal working hours of the laboratory ( Mon - Fri 09.00 to 17.00) https://labtestsonline.org.uk/tests/ancampopr3-antibodies

Notes

There are two major subclasses of ANCA, characterised by staining patterns found when using fixed human neutrophils as substrate under Indirect Immunofluorescence (IIF): 1. C-ANCA (Cytoplasmic or Classical Staining ANCA), denotes a granular cytoplasmic staining pattern on ethanol fixed neutrophils, with some interlobular accentuation. C-ANCA are principally directed against a 29,000 Dalton serine protease, proteinase 3 (PR3) present in the azurophil granules in the cytoplasm of human neutrophils. Other C-ANCA specificities have been detected for cationic protein 57 (CAP57) and cathepsin G. C-ANCA positive is suggestive but not diagnostic of WG, MPA (and its renal limited variant) and Churg-Strauss. C-ANCA positive results must be followed up by ELISA tests for anti-MPO and anti-PR3. 2. P-ANCA (Perinuclear Staining ANCA), denotes a staining pattern present in the perinuclear space of the cytoplasm of ethanol fixed neutrophils. P-ANCA are principally directed against myeloperoxidase (MPO), which is also found in azurophil granules in the cytoplasm of human neutrophils. Other P-ANCA antigen specificities are for elastase and lactoferrin. P-ANCA is associated in MPA and in some cases of WG and Churg-Strauss syndrome although can also be seen in inflammatory bowel disease and other autoimmune diseases. P -ANCA positive results must be followed up by ELISA tests for anti-MPO and anti-PR3. ANCA measurements are not closely associated with disease activity and should therefore not determine treatment increases or decreases. However treatment withdrawal in patients with a persistently positive ANCA is associated with relapse. Different ANCA patterns can be reported on the same sample in different laboratories due to variations in neutrophil substrate.