Comparison of sodium levels between GEM 5000 Blood Gas Analysers and Abbott c8000 Architect Analyser in patients admitted to ED in MUH

Abstract

Background / Problem Identified: Sodium is the major cation of extracellular fluid; it plays an essential role in the normal distribution of water and in the maintenance of osmotic pressure in extracellular fluid compartments. Here in MUH, sodium levels are reported using the GEM 5000 Blood Gas Analyser, as a point of care test in the ED. They also form part of a renal panel and are reported in the Biochemistry lab using the c8000 Abbott Architect, using whole blood and serum/li-heparin samples respectively. The c8000 uses Integrated Chip Technology (ICT), Ion Selective Electrode, diluted (Indirect) to measure sodium, whereas the Gem 5000 uses potentiometric sensors to measure sodium (Direct). Hypo and Hypernatremia are the most common electrolyte disorders. Therefore precise and reliable sodium measurements are crucial for correct treatment of the patient. In recent years, several studies have showed a discrepancy in sodium levels between direct and indirect methods. In general, clinicians consider the two methods to be interchangeable and there is a lack of awareness of the associated discrepancy between methods.