A group of renal pathologists, nephrologists, and transplant surgeons met in Banff, Canada on August 2-4, 1991 to develop a schema for international standardization of nomenclature and criteria for the histologic diagnosis of renal allograft rejection. Development continued after the meeting and the schema was validated by the circulation of sets of slides for scoring by participant pathologists. In this schema intimal arteritis and tubulitis are the principal lesions indicative of acute rejection. Glomerular, interstitial, tubular, and vascular lesions of acute rejection and "chronic rejection" are defined and scored 0 to 3+, to produce an acute and/or chronic numerical coding for each biopsy. Arteriolar hyalinosis (an indication of cyclosporine toxicity) is also scored. Principal diagnostic categories, which can be used with or without the quantitative coding, are: (1) normal, (2) hyperacute rejection, (3) borderline changes, (4) acute rejection (grade I to III), (5) chronic allograft nephropathy ("chronic rejection") (grade I to III), and (6) other. The goal is to devise a schema in which a given biopsy grading would imply a prognosis for a therapeutic response or long-term function. While the clinical implications must be proven through further studies, the development of a standardized schema is a critical first step. This standardized classification should promote international uniformity in reporting of renal allograft pathology, facilitate the performance of multicenter trials of new therapies in renal transplantation, and ultimately lead to improvement in the management and care of renal transplant recipients.

of histomorphologic diagnoses with special reference to the kappa statistic. APMIS 97: [689][690][691][692][693][694][695][696][697][698] 1989.Systems for classification and grading used in pathology should ideally be biologically meaningful and at least be reproducible from one pathologist to another. A statistical method to evaluate reproducibility (non-chance agreement) for several observers using nominal or ordinal categories has been developed and refined over the past few decadesthe kappa statistic. A high level of observed agreement among different pathologists can either signify a high level of reproducibility, if agreement by chance is low, or express a low level of reproducibility, if agreement by chance is almost as high as the observed agreement. Therefore, the observed agreement says nothing in itself, unless it is low. The kappa value, however, indicates how much better the observers are compared to a throw of the dice, and therefore gives the real credit to the agreement which was found. We have developed a user-friendly computer program for calculating inter-and intra-observer agreement of 2 or more observers. By calculating associations between different categories and different observers, the statistic furthermore obtains a function close to the parameter of accuracy. We recommend the use of the above method before a set of nominal or rank scale parameters are used for deciding prognosis and treatment of patients. By submitting a diskette the computer program will be available at no cost.

No abstract

No abstract