QUALITY CONTROL AND ASSESSMENT IN CLINICAL CHEMISTRY AND CLINICAL HEMATOLOGY LABORATORY USING SIGMA METRIC

Abstract

Objectives: To use Sigma metric as a tool for quality control and performance assessment in clinical chemistry and clinical hematology laboratory.

Material and Methods: This study was a descriptive research. The sample consisted of performance assessment and quality control in clinical chemistry and clinical hematology laboratory results. The research instruments were imprecision values assessment by using the percentage of coefficient of variation values from IQC data and the assessment of inaccuracy data were done by using the percentage of bias values from EQA data. Then efficiency of laboratory quality control performance was analyzed by using Sigma metric tool and comparisons between the data points fall outside the control limits from using sigma metric tool and using traditional 2-SD quality control charts were made by using Wilcoxon signed ranks test.

Results: The study of using Sigma metric tool to assess the performance of laboratory quality control in clinical chemistry and clinical hematology parts had been observed from September 2018 to August 2019. The assessment of clinical chemistry laboratory quality control performance in 20 parameters showed the results of world class, excellent, good and marginal performance as 50.0%, 10.0%, 30.0% and 10.0% respectively. Clinical hematology quality controls were done in 6 parameters. The assessment revealed more than 80% of the evaluated parameters were ranked in both world class and excellent performance. The parameters that ranked in world class and excellent performance level could be applied with the Rule of thumb and the Single rule of routine quality control. These rules are flexible with high error-correction capability, low false-rejection and was able to be determined once a day. On the other hands, the parameters that ranked below excellent performance could be applied with multiple rules to improve the quality control assessment. The out-of-control results by comparing using Sigma metric tool and Traditional 2SD quality control, they showed significant difference.

Conclusion: Using Sigma metric tool to increase the performance of routine laboratory control assessment could be furthered applied with the Westgard multi rules and it can help reduce the error of analysis. Both good precision and good accuracy of laboratory quality control performance can ensure maximum safety for the patients and reducing expenses. Sigma metric is good result for psychiatric patient care, for high risk drug surveillance such as lithium and sodium valproate.