Atypical pANCA is a marker for predicting ulcerative colitis (UC). It stands for atypical perinuclear antineutrophil cytoplasmic antibody.

The measurement of perinuclear antineutrophil cytoplasmic (pANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA) has recently been suggested as a valuable and noninvasive diagnostic approach in the differentiation of ulcerative colitis (UC), Crohn's disease (CD) and indeterminate colitis (IC). [L]

Atypical perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) occur in most patients with ulcerative colitis but only in a minority of those with Crohn's disease. [L]

ANCA test results should be interpreted cautiously. The interpretation of the antibody staining pattern using indirect immunofluorescence can be complicated by the presence of other antibodies. In particular, P-ANCA may be difficult to interpret, because anti-nuclear antibodies (ANA) may produce similar staining patterns on neutrophil nuclei. A P-ANCA pattern should not be reported, unless the specimen has been evaluated for the presence of ANA and/or the test has been repeated using formalin fixed slides in addition to ethanol fixed slides.

In addition to ANCA testing, confirmation of the diagnosis should include biopsy. Renal biopsy usually shows pauci-immune necrotizing glomerulonephritis; a biopsy of the lung, sinuses, or nerve will show vasculitis often with fibrinoid necrosis. Necrotizing granuloma is seen in WG and CSS, but not in MPA.

How to interpret your results:

###Please look at all markers of this report together###

When the only positive marker is pANCA, the interpretive comment on the report will read: "Suggestive of ulcerative colitis."

When only one of ACCA, ALCA, AMCA, or gASCA is positive and pANCA is negative, the interpretive comment will read: "Suggestive of Crohn's disease. Pattern is not conclusive for disease behavior risk stratification."

When only one of ACCA, ALCA, AMCA, or gASCA is positive and pANCA is positive, the interpretive comment will read: "Suggestive of inflammatory bowel disease. Pattern is not conclusive for any specific disease form."

When any two of ACCA, ALCA, AMCA, or gASCA are positive and pANCA is positive or negative, the interpretive comment will read: "Suggestive of Crohn's disease with high risk of aggressive disease behavior (development of strictures or fistulae)."

When any three or more of ACCA, ALCA, AMCA, or gASCA are positive and pANCA is positive or negative, the interpretive comment will read: "Suggestive of Crohn's disease with the very high risk of aggressive disease behavior (development of strictures or fistulae)."

When all markers are negative, the interpretive comment on the report will read: "Pattern is not suggestive of inflammatory bowel disease."