Improving the accuracy of chloride measurements through participation in regular external quality assessment programme

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…The new technique highlighted uncorrected biases and allowed the application of a primary reference measurement method (ID-ICP-MS) with a lower LOD of 0.0005 ng L −1 Cd to obtain traceable certified values. 21 The role of EQA schemes, based on metrologically traceable assigned values, for improving the quality of analytical results was further highlighted by the work of Shin et al 22 at the Chemical Metrology Laboratory of Singapore. This research group considered the importance of addressing the accuracy and variability of measurements of serum Cl, a key biomarker for the clinical assessment of acid–base and electrolyte status and a potential predictor of increased mortality risk, with a narrow reference range (96–106 mmol L −1 ), due to strict homeostatic control.…”

“…Metrologically traceable assigned target values for serum Cl in external quality assessment schemes highlighted method biases of clinical analysers. 22 Accuracy-based Cl target values for the Health Services Authority EQA scheme were obtained using an SF-ICP-IDMS primary reference measurement procedure, of which further details are discussed in Section 2, validated with CRMs (NIST SRM 956c and 956d, electrolytes in frozen human serum). The relative deviation from the assigned values of the results obtained with each analytical brand of analysers was assessed.…”