Transplantability tests for isolated preserved organs

The demand for suitable organs for transplantation, and especially for kidneys, requires the establishment of efficient organ procurement and preservation programmes. The success of such programmes depends, amongst other things, on the ability to preserve organs for long periods of time and the ability to assess organ viability before transplantation. The characteristics of an ideal criterion of viability, or transplantability, are discussed. A short survey of currently used, or suggested, criteria is presented. A new method is suggested that employs the dynamic response of the organ. The organ is considered as a 'black box' that is repetitively subjected to small perturbations in its input. System-identification techniques are used to identify the dynamic parameters of the organ with respect to the specified input. Using a priori statistical data, the parameter space is divided into several regions, each denoting a different state of viability. The transplantability of the organ is determined by the location of the parameter vector in the parameter space. Prognostic decisions can be made by calculating the gradients of this vector, and estimating its location in some near future time.