The Influence of Flow Rate on the Concentration of Uric Acid in Human Parotid and Submandibular Saliva

¹ Dental Hospital and School, University Department of Medicine, Western and Royal Infirmaries and Centre for Rheumatic Diseases, Glasgow, Scotland

Uric acid concentration was measured in parotid and submandibular saliva collected at varying flow rates.

The uric acid concentration was inversely related to flow rate, and a straight line relation was obtained when log (vol/min) was plotted against log (uric acid concentration).

In parotid saliva the mean uric acid concentration fell from 4.0 ± 0.43 mg/100 ml at low flow rates to 1.7 ± 0.28 mg/100 ml at high flow rates. The concentrations were lower in submandibular saliva 3.3 ± 0.46 mg/100 ml and 1.3 ± 0.12 mg/100 ml, respectively.

It is concluded that in studies of uric acid, saliva should be collected at flow rates greater than 1 ml/min, so that there is little variation in uric acid concentration and precise measurement of flow rate is unnecessary.