Validation of the salivary urea test as a method to diagnose chronic kidney disease.

Background: Serum urea correlates very well to sali- vary urea, which can be used as a low-cost, eas- ily accessible and noninvasive diagnostic method for screening patients in early stages of kidney disease, especially in developing countries where resources are limited, giving the possibility of establishing sec- ondary prevention programs later. Methods: One hundred and one people were enrolled: 11 with creatinine clearance (CrCl) less than 10 ml/min per 1.73 m 2 ; 10 with CrCl of 11-20 ml/min per 1.73 m 2 ; 12 with CrCl of 21-50 ml/min per 1.73 m 2 ; 26 with CrCl