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

Background: Serum urea correlates very well to salivary urea, which can be used as a low-cost, easily 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 secondary 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.