Application of Sigma Metrics for the assessment of analytical quality in clinical biochemistry laboratories in Sudan: A Pilot Study

Background: The ultimate goal of clinical laboratories in healthcare service is to provide accurate, precise, relevant and comprehensive data that can be applied to the medical management of patient. Therefore, the evaluation of laboratory performance is critical to maintaining accurate laboratory results. However, six sigma provide uniquely defined scale with which clinical laboratories performance can be assessed. This study aimed to evaluate the analytical quality in 10 clinical laboratories in Khartoum state using the sigma metrics application. Materials and Methods: The six months (January to June 2012) internal quality control (IQC) and inter-laboratory peer comparison data for 10 clinical biochemistry laboratory was analyzed targeting glucose; urea and creatinine. For target parameters in each laboratory, Coefficient of variation (CV) was calculated from IQC, percentage bias was calculated from inter-laboratory peer comparison and total allowable error was followed as per Clinical Laboratory Improvement Amendment (CLIA). Sigma metrics were calculated from CV, percentage bias and total allowable error for target parameter in each laboratory. Results: CVs were found to be ? 5% for glucose, urea and creatinine in (9, 8, and 4) Out of 10 laboratories; respectively. For glucose test sigma value (?3) was attained by 2 out of 10 laboratories whereas all laboratories achieved unacceptable sigma values (?3) for urea and creatinine tests. Conclusion: These study findings revealed that all the laboratories achieved unsatisfactory sigma values for targeted parameters. This demonstrates poor performance and low consistency of testing results. These laboratories need an appropriate interpretation of daily IQC data and develop prompt corrective and preventive actions to monitor the routine performance of the testing processes.