In this study, we examined the clinical significance of the measurement of uric acid in saliva, after investigating correlation of the uric acid concentration in serum and saliva.
Methods: One hundred ninety-seven healthy volunteers and outpatients were enrolled in this study (male: 158, 39.8+/-15.4 years, female: 39, 40.9+/-16.7 years).
For treatment of hyperuricemia, 28 and 12 patients had taken benzbromarone and allopurinol, respectively. Daily changes of the uric acid concentration in serum and saliva were examined in six healthy volunteers.
Two milliliters of blood and saliva were collected in the morning and quantitative analysis of uric acid was carried out by enzyme method.
Results: (1) The uric acid concentration in serum and saliva showed a significant correlation in 197 subjects (r= 0.307, p< 0.01).
(2) Higher significant correlation was recognized in the uric acid concentration between serum and saliva in 164 who excluded the subjects whose uric acid value in saliva was higher than serum (r=0.47, p<0.001).
(3) In 26 (92.8%) of 28 treated with benzbromarone, the salivary uric acid concentration was higher than serum.
(4) In 12 treated with allopurinol, the serum uric acid concentration was higher than saliva.
(5) The uric acid concentrations in serum and saliva were high at early morning and fell in the evening.
Conclusion: The measurement of salivary uric acid was useful for diagnosis of hyperuricemia, and saliva had played an important role in uric acid excretion.
In addition, benzbromarone may greatly be participating in the mechanism of uric acid excretion in salivary glands.