Impaired cognitive functions were reported in uremia. The purpose of this study was to quantify the functional state of taste in various stages of chronic renal failure. Taste sensitivity was assessed by asking the subjects to identify test solutions of sucrose (‘sweet’), NaCl (‘salty’), citric acid (‘sour’), quinine (‘bitter’) and water presented randomly in five concentrations. The number of recognition errors was statistically analyzed as a measure of taste acuity. Four groups of subjects were examined: 20 nondialyzed uremic patients, 23 patients on regular hemodialysis, 20 patients suffering from chronic diseases with normal renal functions and 22 healthy volunteers. Nondialyzed and dialyzed uremic patients younger than 55 years had a significant impairment of recognition in all taste modalities when compared to both control groups. This was less obvious in patients older than 55 years. No differences in taste recognition were found between dialyzed and nondialyzed uremics of all ages. In the younger age group, however, there was improvement in the recognition of ‘sour’ and ‘bitter’ when tested before and immediately after the dialysis session. As zinc deficiency was excluded in all of the uremic patients we conclude that the impaired taste perception is another subtle facet of the uremic neuropathy.

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