Correlation of creatinine levels in saliva and plasma in normal subjects and renal patients.

Whole saliva and serum creatinine levels were evaluated in three normal subjects and 12 patients with chronic renal failure receiving regular hemodialysis treatments. Ratios of the serum vs. saliva creatinine levels ranging from 4.5 to 30.0 were found. Repeated studies also revealed marked intra-subject variations in these ratios. We conclude that the monitoring of whole saliva creatinine levels is only of limited value in accurately predicting serum or plasma creatinine levels, despite its appeal of simplicity, convenience and non-invasiveness. Its value in the qualitative monitoring of renal function may, however, be useful.