Evaluation of the Jokoo-ION 150 AC: Guidelines for the evaluation of analysers by ion-selective electrodes

The Jokoo-ION 150 AC is an automatic sodium, potassium and chloride analyser which uses ion-selective electrodes.The sample mode can be whole-blood, serum or urine. To evaluate a urine sample, a previous dilution (1:6) with the standard 1 solution is required. For three concentrations of control materials, the total precision (CV) ranged from 0.17 to 1.22% for sodium, 0.22 to 1.69% for potassium and 0.16 to 0.74% for chloride.The system demonstrated acceptable performance in detection limit, linearity, drift and carry-over. Patients' results from ION 150 AC correlated well with those from a SMAC II and an IL 943. In a study on potential interferences, a slightly negative interference with potassium was found with increases in lithium; and only high ammonium ion concentrations caused a positive interference on the potassium ion. A slightly positive interference of bromide on the chloride ion was also found.The electrode slope, electrode response, sample temperature and pH effect, effects of high concentrations of proteins or lipids, and haematocrit influence on the sodium, potassium and chloride ion concentration were also evaluated. The strategy adopted in this study provides an ideal framework for future evaluations of ionselective electrode analysers.