2022 ACR/EULAR Classification Criteria for Microscopic Polyangiitis (MPA)

The American College of Rheumatology (ACR) and EULAR reported criteria for microscopic polyangiitis (MPA).

Parameters:

(1) p-ANCA or anti-myeloperoxidase-ANCA positivity

(2) c-ANCA or anti-proteinase3-ANCA positivity

(3) pauci-immune glomerulonephritis

(4) lung fibrosis or interstitial lung disease

(5) sino-nasal symptoms

(6) maximum absolute eosinophil count

Parameter	Finding	Points
max absolute eosinophil count	< 1 * 10^9/L	0
	>= 1 * 10^9/L	-4
lung fibrosis or interstitial lung disease	no	0
	yes	3
sino-nasal symptoms	no	0
	yes	-3
c-ANCA or anti-proteinase3 ANCA	no	0
	yes	-1
pauci-immune glomerulonephritis	no	0
	yes	3
p-ANCA or anti-myeloperoxidase ANCA	no	0
	yes	6

total score =

= SUM(points for all of the parameters)

Interpretation:

• minimum score: -8

• maximum score: 12

• A score >= 5 indicates MPA in a patient with a small/medium vessel vasculitis, with exclusion of vasculitis mimics.

Performance:

• The sensitivity was 91% and specificity 94%.

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