Aim of the study: Blood gas analysis (BGA) is essential for the diagnosis and management of acid-base imbalances. We evaluated and compared the analytical characteristics of the new GEM® Premier™ 5000 (GP5000) (Instrumentation Laboratory, Bedford, MA, United States) BGA point-of-care (POC) device with those of the GEM® Premier™ 4000 (GP4000) (Instrumentation Laboratory, Bedford, MA, United States) and RapidPoint® 405 (RP405) (Siemens Healthcare, Milan, Italy) POC analyzers. The effect of sample mixing on patient results was also studied.
Material and methods: Quantitative measurement of pH, pCO2, pO2, Na+, K+, Cl-, iCa2+, glucose, lactate, tHb, COHb, MetHb, O2Hb, HHb and Hct were carried out. The imprecision study (IS) and method comparison study (MS) were performed according to CLSI EP guidelines, using respectively internal as well as external quality controls (IS) and whole blood samples collected from the routine analysis (MS).
Results: GP5000 demonstrated satisfactory characteristics in the IS showing comparable (GM4000) or even better (RP405) imprecision results than the routine POC devices. Good performance was observed in the MS both using GP4000 and RP405 as reference instruments. Pre-analytical sample management can heavily affect the accuracy of BGA results. In the specimen mixing evaluation, a significant improvement in results accuracy was observed when mixing procedures were more meticulous.
Conclusions: Considering the overall analytical performance observed, the ease of use of the system, the rapid time-to-results and the innovative Intelligent Quality Management technology (iQM2®), GP5000 seems suitable to be used in clinical care for safe patient management. Additionally, effective sample mixing upon draw and before analysis is strongly advisable in order to ensure the most clinically reliable BGA results.
Keywords: Blood gas analysis; CO-oximetry; Imprecision; Method comparison; Point-of care testing; Pre-analytical phase.
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