Observer agreement in the scoring of the activity and chronicity indexes of lupus nephritis.

The present study was designed to evaluate the observer reliability in the scoring of the activity and chronicity indexes, among three experienced pathologists, in renal biopsies from lupus nephritis (LN). Twenty-five renal biopsies of LN, were evaluated independently by three pathologists to assess the interobserver variability. For the intraobserver agreement, 5 biopsies were evaluated twice by each pathologist. The interobserver agreement for the scoring of the activity and chronicity indexes was 0.81 and 0.86, respectively. In the intraobserver agreement the same results were: for the pathologist 1, 0.95 and 0.70; for the pathologist 2, 0.91 and 0.55; for the pathologist 3, 0.89 and 0.82. In conclusion the agreement for the scoring of the activity and chronicity indexes in biopsies from LN was excellent.