Electrolyte measurement of critically ill patients is frequently requested in emergency central laboratory. These are either obtained from Point of Care (POC) electrolyte analysers on urgent basis or processed on the autoanalysers. Accurate and rapid measurement of electrolyte such as sodium and potassium help in development of focused course of treatment. Aim: To compare the results of serum electrolytes measured on four different autoanalysers working on the same principle of direct Ion

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... ive Electrode (ISE) measurement, to determine the extent of agreement amongst them. Materials and Methods: This prospective comparative study was done using 200 patient samples obtained from the Central Biochemistry Laboratory of Lok Nayak Hospital, New Delhi, India. Serum samples were analysed on four different analysers for electrolytes (Na+ and K+), two Roche AVL electrolyte analysers and two Randox Imola autoanalysers working on the same methodology of direct ISE measurement. Means, standard deviations and coefficient of variations were calculated. The Bland-Altman plots were used to compare the results of two different assays and to quantify the limit of agreement. The p-value <0.05 was considered statistically significant. Results: The mean value for sodium was 135±10.6 mmol/L and 136±10.4 mmol/L for Roche AVL 1 and 2 electrolyte analysers; 140±10.9 mmol/L and 140±10.7 mmol/L for Randox Imola 1 and 2 autoanalysers. Similarly, the mean value for potassium were 4.53±2.86 mmol/L, 4.32±1.03 mmol/L, 4.33±0.97 mmol/L and 4.35±0.94 mmol/L for AVL 1, AVL 2, Imola 1 and Imola 2, respectively. The Bland-Altman plots have shown a good agreement of -0.34 to 0.31 for serum potassium for Imola 1 and AVL 1 however, no such agreement was found for sodium values on inter-analyser comparison. The Bland-Altman plots were used to compare the results of two different assays and to quantify the limit of agreement. The p-value of <0.05 was considered statistically significant. Conclusion: Serum electrolytes obtained from elec [...]