摘要：The effect of storage time and temperature on the immunological turbidimetric measurement of a low concentration of albumin in urine was investigated. In storage at -20°C, the albumin level decreased, but the rate of this decrease differed considerably among specimens. However, under storage at room temperature for 2 weeks, or at 4°C for 5 weeks albumin levels did not show significant changes. At -40°C and -80°C there were only slight decreases. At -40°C decreases were slightly greater than at -80°C. Therefore, -80°C was found to be the optimal temperature for long-term storage of urinary albumin. Some of the specimens showed a 50% decrease in albumin level after storage for 9 weeks at -20°C, but remained unchanged after storage for the same period at -80°C. A pair of specimens preserved at -20°C and -80°C were isolated by SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). After electrophoresis, urinary proteins were stained by silver staining to observe bands, and albumin content was determined by immunoblotting. A decrease in albumin concentration was also observed by densitometric detection.
