Comparison of blood gas, electrolyte and metabolite results measured with two different blood gas analyzers and a core laboratory analyzer

Abstract

Background. Blood gas analyzers (BGAs) are important in assessing and monitoring critically ill patients. However, the random use of BGAs to measure blood gases, electrolytes and metabolites increases the variability in test results. Therefore, this study aimed to investigate the correlation of blood gas, electrolyte and metabolite results measured with two BGAs and a core laboratory analyzer. Methods. A total of 40 arterial blood gas samples were analyzed with two BGAs [(Nova Stat Profile Critical Care Xpress (Nova Biomedical, Waltham, MA, USA) and Siemens Rapidlab 1265 (Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA)) and a core laboratory analyzer [Olympus AU 2700 autoanalyzer (Beckman-Coulter, Inc., Fullerton, CA, USA)]. The results of pH, pCO₂, pO₂, SO₂, sodium (Na⁺), potassium (K⁺), calcium (Ca^{+ 2}), chloride (Cl⁻), glucose, and lactate were compared by Passing-Bablok regression analysis and Bland-Altman plots. Results. The present study showed that there was negligible variability of blood gases (pCO₂, pO₂, SO₂), K⁺ and lactate values between the blood gas and core laboratory analyzers. However, the differences in pH were modest, while Na⁺, Cl⁻, Ca²⁺ and glucose showed poor correlation according to the concordance correlation coefficient. Conclusions. BGAs and core laboratory autoanalyzer demonstrated variable performances and not all tests met minimum performance goals. It is important that clinicians and laboratories are aware of the limitations of their assays.

Key Words::

• Blood gas analyzer
• electrolytes
• metabolites
• interchangeability
• method comparison

Funding and ethical approval

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The ethics committee of Gulhane School of Medicine approved this study (REC number: 2154, Date: September 16, 2013).

Authors’ contributions

Metin Uyanik and Erdim Sertoglu researched literature and conceived the study. Huseyin Kayadibi performed the statistical analysis of data. Muhittin A. Serdar, Ismail Kurt, Cumhur Bilgi and Metin Uyanik were involved in protocol development, gaining ethical approval, patient recruitment and data analysis. Erdim Sertoglu and Serkan Tapan wrote the first draft of the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript.

Acknowledgements

The authors would like to thank Fatih Yesildal, MD, and Irfan Sener, MD, for their help.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.