van Daalen EE, Hruskova Z, Trejo MACW, et al. - This study was sought to evaluate the current position of the histopathologic classification of ANCA-associated GN. Researchers carried out a validation study with newly collected data from 145 patients from ten centers worldwide, including an analysis of interobserver agreement on the histopathologic evaluation of the kidney biopsies. This research also enrolled a meta-analysis on previous validation studies and a validation of the recently proposed ANCA kidney risk score. It was demonstrated that the crescentic and mixed classes appear to have a similar prognosis, also after adjusting for differences in patient populations, treatment, and interobserver agreement. Nevertheless, at this stage, Because the reported confidence intervals do not exclude important differences in prognosis and because an important histopathologic distinction would be lost, they are not inclined to merge the crescentic and mixed classes.