Validation of an automatic urea analyser used in the continuous monitoring of hemodialysis parameters

The validation of an automatic urea analyser used in the monitoring of hemodialysis processes is reported. The analyser can indirectly determine dialysis parameters as dialysis delivery (KT/V) and protein catabolism (PCRn). These parameters are useful for the prescription and optimization of hemodialysis. The analyser, based on a previously-reported flow-injection analytical biosystem, was connected on-line to the effluent of a dialysis machine during several hemodialysis sessions. The urea concentration data were continuously processed and dialysis parameters were obtained in quasi real time by means of the integration of an adjusted time-dependent exponential function. These values were compared with those obtained by applying the methods traditionally employed in hospital laboratories. The evaluation comprised 24 data sets from several patients of different gender and age. No significant differences were found between the KT/V and PCRn results obtained with the usual method and those results produced by the analyser proposed here.