Evaluation of Saliva for Monitoring Renal Function in Haemodialysis Patients at University of Port Harcourt Teaching Hospital

In this study, the concentrations of urea were assayed in both blood and saliva of 130 haemodialysis patients; before haemodialyis(pre-haemodialysis) and after haemodialysis (post haemodialysis); and 60 healthy individuals who made up the control group. The method used for urea assay was urease method. The mean±SD concentrations of salivary urea in pre and post haemodialysis patients, as well as control group, were 17±0.6 mmol/l, 9.1±0.5 mmol/l and 4.0±0.3 mmol/l respectively. The mean±SD concentrations of blood urea in pre and post haemodialysis patients, as well as control group, were 21.6±0.5 mmol/l, 9.1±0.4 mmol/l and 4.2±0.2 mmol/l respectively. The correlation coefficient between blood and salivary urea in pre-haemodialysis patients is 78.8% while that for post haemodialysis patients is 60.6% and for the control group is 90%. The ANOVA results of salivary urea in the three groups (pre, post and control) showed a significant difference with P-value ˂0.05. The ANOVA results of blood urea in the three groups (pre, post and control) showed a significant difference with P-value ˂0.05. From the various results obtained, saliva can serve as a diagnostic biofluid for renal disease especially with the salivary urea as the biomarker. Also, the salivary renal biomarker (urea) responds to changes in concentrations after therapeutic consideration. This study is in consonance with other literature that saliva is a diagnostic fluid for kidney disease; however, there is a need to carry out more research works to continually unveil the diagnostic potential of saliva in kidney disease.