Comparison of electrolyte levels in serum and plasma

• Author Details:   
• C. K. Vijayasamundeeswari
• N. Ananthi
• R. Sudha

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Introduction: Measurement of electrolytes plays a significant role in the management of critically ill patients. The accuracy of electrolyte measurement depends on a number of pre-analytical variables. Electrolytes are the positively and negatively charged ions that are essential for normal cellular functioning of the body. Most of the metabolic processes are mediated through electrolytes. Electrolyte abnormalities are seen in a number of conditions and can end up in life threatening conditions unless accurate results are given from the laboratory.
Aim: To check the effect of different storage temperature on estimation of electrolyte values using serum and plasma samples of venous blood.
Materials and Method: Analysis of electrolyte levels was conducted in venous blood samples collected from 30 patients stored under room temperature and at 2-4 ⁰C. Serum and plasma electrolytes-sodium [Na], potassium [K], chloride [Cl] were analysed using electrolyte analyser at different time intervals and storage conditions. The samples at room temperature were analysed immediately after collection and at 6hours, 12hrs, 24 hrs, 36hrs and 48hrs.The samples kept at 2 - 4⁰C were also analysed at 6hrs, 12hrs, 24 hrs, 36hrs and48hrs simultaneously.
Results: Serum K, Cl has no significant changes till 48 and 12hrs, both at 2-4⁰C and at room temperature respectively. Serum Na at 2-4⁰C is relatively stable for a longer time than its counterpart stored at room temperature (48hrs vs 36 hrs). Similarly, plasma samples also showed more stability at 2-4⁰C than at room temperature.
Conclusion: Estimation of electrolytes as early as possible at proper storage conditions is the best solution to avoid analytical errors.

Keywords: Sodium, Potassium, Chloride, Electrolytes, Storage Temperature