Effects of Temperature and Delay in Separation of Serum on Potassium and Sodium Levels
Abstract
Background: Potassium and sodium estimation are considered two of the important tests to evaluate kidney functions. Clot contact time and temperature have variable effects on the laboratory investigations, leading to misdiagnosis and inappropriate treatment decision. Objective: The current study aimed to estimate the maximum acceptable time delay between sample collection and serum separation as well as to analyze the effect of different temperatures on potassium and sodium stability. Materials and methods: A total of 50 healthy individuals (n=50) of both genders and ages ranging from 17 to 30 years attending to Omdurman Islamic university were included in this cross-sectional study during the period from January to March, 2016. Blood specimens were collected from each participants, the centrifugation of whole blood stored at room temperature was delayed for 2 hours and 4 hours, serum was analyzed immediately, and after stored at 4oC for 24hrs, 48hrs and 96hrs by using ion-selective electrodes, and compared the values with those of matched samples that had been centrifuged within 0.5 hours after whole blood collection. Results: Storage temperature causes potassium to significantly increase after the entire 24hrs, 48hrs and 96hrs, while sodium was found to have increased significantly at 48hrs and 96hrs. On the other hand Delaying in separation insignificantly affect either the potassium or sodium for a period of up to 4 hrs. Conclusion: The maximum clot contact time intervals which have no effect on the stability of both sodium and potassium are found to be 4hours, and the stability of both are found to be sensitive to temperature and duration of storage of the samples.
References
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