One-year’s experience of a ‘repeat analysis’ quality programme for blood gas analysers

Abstract  The aim of this study was to determine the value of a quality assurance (QA) programme based on the repeat analysis principle, where a sample is analysed at one site, and sent to another site for repeat analysis and the comparison of the two sets of values. Once each day a routine blood gas sample, collected from a patient in the Intensive Therapy Unit (ITU) of the hospital, was analysed by the ITU nurse on the ITU blood gas analyser. The air bubble was expelled and the sample sealed and sent to the biochemistry laboratory immediately. The sample was re-analysed in the biochemistry laboratory. This programme was continued for a year. The biochemistry laboratory results (gold standard) were compared with the ITU results and rule breaches were notified to ITU immediately after the repeat analysis. All results were graphed and linear regressions and correlation coefficients calculated. The correlation coefficients ranged from r 2=0.9317 for pH to r 2=0.4381 for pO2. All parameters except pO2 and Na+ gave satisfactory correlations. The Na+ results should be adjusted by inserting a slope and intercept. It is suspected that improvement in the pO2 would be possible if the time between ITU and biochemistry analyses could be reduced from its current levels.