The One-Hour Clearance Rate Hour Creatinine in Healthy Men

In 20 normal young men, three consecutive, morning, 1-hour creatinine clearance studies, measured on both of two separate days after either modest or heavy hydration, were compared with each other and those of the 24-hour studies done the same day. Under either circumstance of hydration, differences between 1-hour and 24-hour clearance rates were not significant. Heavy hydration diminished the correlations between short-term and long-term clearance rates, but with one exception, the correlations remained significant. Measurements of clearance from the various one-hour collection periods were similar to one another. We conclude that values obtained from 1-hour creatinine clearance studies are reasonably reproducible and that carefully controlled 1-hour clearance studies can be used instead of 24-hour studies to determine glomerular filtration rate in groups or individuals.