Impact of water quality and interferences of ion selective electrodes on electrolyte dosage

Fluid and electrolyte imbalances are frequently encountered in hospital settings and can significantly affect patient health, influencing vital functions such as nerve conduction, muscle contraction, and acid-base balance. Accurate determination of serum ion concentrations is essential for effective clinical management, and various analytical methods, including ion-selective electrodes (ISE), are widely employed for this purpose. This study focuses on the use of ISE technology for measuring sodium (Na⁺), potassium (K⁺), and chloride (Cl⁻) levels in biological samples, with particular attention to potential interferences and the impact of water quality on assay accuracy. Our laboratory employs the indirect ISE method using the Abbott Architect ci 8200 analyzers, ensuring high specificity and precision. A comprehensive quality management system (QMS) in accordance with ISO 15189 standards is implemented to monitor all stages of electrolyte analysis, from pre-analytical to post-analytical processes. This system includes rigorous internal and external quality control measures, regular calibration, and the use of high-purity water, processed through a multi-stage water treatment system to minimize contaminants. The results from our quality control processes demonstrate that the laboratory consistently maintains the accuracy and reliability of electrolyte measurements. By addressing interferences related to sample matrix effects, assay conditions, and water quality, we aim to provide clinicians with the most accurate data for informed decision-making in patient care.