Correlations of pseudouridine in 8-hour and 24-hour urinary samples determined by high-performance liquid chromatography.

The correlations of Pseudouridine (psi) values in 8 h and 24 h urinary samples from 23 healthy persons were determined. Pseudouridine in the 8 h urinary samples was measured by high-performance liquid chromatography and the 24 h excretion was calculated from the results of three 8 h determinations. Simultaneous determinations of urinary creatinine were performed by Jaffe's reaction. Based on the 8 h values of urinary Pseudouridine the results demonstrated a constant excretion of Pseudouridine in the 24 h periods, if the values were related to the urinary creatinine. The precision in using this ratio as an indicator for normal 24 h excretion of Pseudouridine was 90.5% for males and 92.5% for females.