DETERMINING URINARY CREATININE BY ALKALINE PICRATE METHOD AND HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Urinary creatinine has been widely analyzed in research fields concerning body composition and muscular activities since the amount of creatinine excretion in urine is nearly proportional to the muscular mass in humans, and the amount in an individual is nearly constant. And also research studies pointed out the decrease in urinary creatinine after acute exercise. Effects of exercise upon urinary creatinine have been, furthermore, reported. However, there are research studies indicating that Borsook method shows slightly lower values than Folin method and that the liquid chromatographic procedure gives results that are lower than those obtained by an alkaline picrate method(APM) and the procedure is more precise. The purpose of this study is, therefore, to clarify the preciseness of APM in a case of determining urinary creatinine. Thirty one healthy college male students volunteered to be subjects in this study. Urinary creatinine values by APM was compared with those by a high performance liquid chromatography(HPLC). A Folin-Wu method was used for APM. This study found that urinary creatinine values by HPLC is significantly lower than those by APM as Patel and George indicated although there was a significant correlation between the values by HPLC and APM. And also it was found that a significant regression formula, y=1.0168x-118.099(where x=urinary creatinine concentration by APM),should be used to obtain more precise creatinine concentration in urine which is y values, urinary creatinine concentration by HPLC, if HPLC is not available