In addition to providing diagnosis the renal biopsy can provide prognosis and possibly therapeutic guidance. This is the reason for pathologic classification of diseases. One of the latest proposed classification is ANCA-associated vasculitis (AAV). Ford et al. validated and examined reproducibility of the classification.
The classification divides glomerular lesions of AAV into 4 categories; focal, crescentic, mixed and sclerotic. The patients with sclerotic pattern had the poorest outcome while patients with crescentic pattern had significantly improved renal function after treatment. The renal function at presentation and tubulointerstitial fibrosis also affected the outcome.
For reproducibility study sclerotic pattern was the most agreed upon. The rest patterns were classified less consistently. The pathologists seemed to have problems agreeing on normal glomeruli, crescents and fibrinoid necrosis.