Creatinine and specific gravity (relative density) measurements both allow differences in urine concentration to be taken into account in determining urine cotinine concentrations. In this study we demonstrate that the variance of urine cotinine measurements is reduced comparably when either creatinine or specific gravity measurements are used for correction. This reduction in variability impro...

BACKGROUND The usage of urine protein/creatinine ratio to estimate daily urine protein excretion is prevalent, but relatively little attention has been paid to the influence of urine concentration and its impact on test accuracy. We took advantage of 24-hour urine collection to examine both urine protein/creatinine ratio (UPCR) and daily urine protein excretion, with the latter as the reference...

The urinary excretion rate is calculated based on short-term, defined time sample collections with a known sample mass, and this measurement can be used to remove the variability in urine concentrations due to urine dilution. Adjustment to the urinary excretion rate of hippuric acid was evaluated in 31 healthy volunteers (14 males and 17 females). Urine was collected as short-term or spot sampl...

Aim—To evaluate the reliability of dipstick measurements of urine specific gravity (U-SG). Methods—Fresh urine specimens were tested for urine pH and osmolality (U-pH, U-Osm) by a pH meter and an osmometer, and for U-SG by three diVerent methods (refractometry, automatic readout of a dipstick (Clinitek-50), and (visual) change of colour of the dipstick). Results—The correlations between the vis...

There is good correlation between the specific gravity and osmolality of urine obtained from neonates and adults, if specimens contain neither protein nor glucose. The regression equations between specific gravity and osmolality, however, differ considerably between the two age groups, maturation to the adult regression occurring within the first 5 years of life. Specifically derived regression...