In patients who are receiving chronic hemodialysis treatments, concentrations of creatinine and uric acid in serum correlated significantly with those in simultaneously drawn unstimulated whole saliva, both before and after dialysis. Similar correlation was shown also in a group of moderately azotemic patients who had not yet entered the chronic hemodialysis program. Use of whole saliva in these tests instead of blood samples may reduce the iatrogenic component in anemia, the frequency of venipunctures and of blood samplings. This may be a boon particularly in pediatric patients and in other patients where, due to a variety of reasons, this is desirable.