The storage time and temperatures effect on the stability of some biochemical variables in sera samples

Background:Laboratory results are of great importance for the accuracy of the diagnosis and the laboratory environment directly affects the accuracy of the results.The blood test is one of the most important diagnostic methods that assess the health of patients and healthy people. Objectives:study the effect of several time intervals and different low temperatures of samples storage on serum glucose, urea, Na +, and K + concentration and to study the osmolarity at the same conditions. Methods: 20 blood samples were obtained from 20 persons,centrifuged and divide into 3 parts. The first part was analyzed, and the second part was respectively stored for 3, 6 and 9 weeks in the refrigerator. The third part was kept in a deepfreeze and stored for 3,6 and 9 weeks.The samples were kept in different temperature conditions for 9 weeks, and then the stability of some biochemical variables was studied. Results:The results indicated that there are important changes. Serum glucose samples show a significant increase in glucose level after 6 and 9 weeks in refrigerator and freezing. Significant decrease in urea level after 9 weeks storage in refrigerator and freezing. A non-significant increase in sodium level after storage in refrigerator and freezing during all periods. Significantly increased in Potassium level after 3,6 and 9 weeks storage in refrigerator and freezing. The mean glucose level was increased significantly (P<0.05) throughout the study. On the other hand, the analysis showed that the mean urea level was decreased significantly (P<0.05) at the same conditions.Sodium has risen from a level of 159.95 ± 4.21to a level of 195.84 ± 6.57 in case of refrigerating and have risen from a level of 159.95 ± 4.21to a level of 184.20 ± 4.94 in case of freezing. As for the potassium concentration, it recorded an average increase from a level of 3.72 ± 0.18 to a level of 7.62 ± 0.29 in case of refrigerating and has risen from a level of 3.72 ± 0.18 to a level of 5.43 ± 0.11in case of freezing.The results showed thata nonsignificant increase in osmolarity level after storage in the refrigerator and freezing in comparison to the initial time.The results show a highly significant correlation between six parameters, a significant correlation between two parameters and a nonsignificant correlation between two parameters as shown in result tables. The importance of this study lies in explaining the laboratory results of samples that are stored before testing for certain periods and under low temperatures. Merzah et al (2021):Storage time and temperatures on stability of some biochemical variables in serum Feb 2021 Vol. 24 Issue 2 http://doi.org/10.36295/ASRO.2021.24228 Health Medicine & Public Annals of Tropical Conclusion: The conclusion from this study is analyzing the levels of glucose, urea, sodium, and potassium in addition to the osmolarity, that keeping serum samples under low-temperature conditions such as a refrigerator or freezer will lead to a variation in the concentrations of biochemical variables.