Anti-Neutrophil cytoplasmic antibody (ANCA)
Anti-neutrophil cytoplasmic antibodies (ANCA) are found in
several types of vasculitis. Samples for ANCA are initially tested
by immunofluorescence on neutrophils. Positive samples are then
further tested by multiplex flow immunoassay for specific
antibodies against either proteinase 3 (PR3) or myeloperoxidase
(MPO). In general, a classical c-ANCA pattern corresponds to PR3
reactivity whilst a perinuclear p-ANCA pattern corresponds to MPO
reactivity. Atypical ANCA patterns do not usually correspond to
These tests are used to diagnose vasculitis and to monitor
disease activity. Infections and autoimmunity can produce false
positive tests reducing the specificity of ANCA testing.
Specimen transport: At room temperature
Repeat frequency: No more frequently than every
four weeks, except when plasmapheresis is being done.
Special precautions: None
Normal reference ranges: Neg
Volume and sample type: 7ml clotted blood
Turnaround time (calendar days from sample
receipt to authorised result): Median - 3, 95th percentile - 7
We will undertake urgent same day testing during laboratory
opening hours provided that the laboratory is contacted by phone
and the sample arrives before noon.
Indications for the test: ANCA testing is
helpful in patients with vasculitis affecting the kidneys
Factors affecting the test: Positive ANA, ie.
the presence of other autoantibodies. False positives see in
Guidelines are provided in the following
reference: Addendum to the International Consensus
Statement on Testing and reporting of ANCA Am J Clin Pathol 2003;
Clinical workstation reference: ANCA
(Last updated October 7th