ABG RAW DATA
Validation of the OMNI S b221 Blood Gas Analyser method for point-of-care testing at the largest Academic Hospital in the Southern Hemisphere Ernest Philani Buthelezi1*, Edwin Rampota2, Matumi Mphogo2, Florence Marule2 and Donald M Tanyanyiwa3,4 1. Department of Health, Laboratory and Blood Services, Johannesburg, South Africa. 2. Department of Chemical Pathology National Health Laboratory Service, Johannesburg, South Africa. 3. Department of Chemical Pathology, University of the Witwatersrand, Johannesburg, South Africa. 4. Department of Chemical Pathology, Sefako Magkatho Health Sciences University, Pretoria, South Africa. *Correspondence: Ernest Philani Buthelezi1, Department of Health, Laboratory and Blood Services, Johannesburg, South Africa. Telephone: +27 11 694 3714; Mobile phone: +27 82 558 9498. Email: Philani.Buthelezi@gauteng.gov.za Abstract Introduction: The introduction of a new method or new analyser is a common occurrence in laboratory practice. Since Astrup developed the first analyser in the 1950s, blood gas analysers have evolved from the measurement of basic pH, partial pressures of oxygen (pO2) and carbon dioxide (pCO2) to the measurement of various forms of haemoglobin, serum electrolytes, and other metabolites. These analysers offer the best form of point-of-care testing (POCT). When a new POCT analyser is obtained, the performance of the analyser should be evaluated by comparison to the central laboratory or outgoing analysers in cases of replacements. Objectives: Evaluation of method performance of pH, pCO2, pO2, glucose, lactate and electrolytes on Roche Cobas OMNI S b221 (Arterial blood gas) ABG analyser. Materials and Methods: To analyse the method performance of the pH, pO2, pCO2, glucose, lactate and electrolytes (Na+, K+ Ca++) on Cobas b221 arterial blood gas (ABG) analyser by comparing 40 samples run on Cobas b221 with the results obtained from Radiometer ABL700, GEM PREMIER for all the parameters and the Roche Hitachi 917 analyser to compare two electrolytes (Na+ and K+). The correlation coefficient was calculated for the results obtained from each paired set of instruments (ABL 700 vs GEM PREMIER and ABL 700 vs OMNI S b221). Comparability between analyser methods performance was determined using Scatter plots. Results: The correlation coefficient between the paired analytical platforms were all between 0.81 and 0.99, demonstrating a good correlation. The coefficient of variation (CV) for all the parameters were less than 2 also demonstrating good precision. Conclusion: ABG b221 analyser correlated well with the outgoing ABG ABL 700 analyser, GEM PREMIER ABG and the central laboratory analyser, Roche Hitachi 917 and therefore, verified as a good platform to run arterial blood gas samples.