Assessment of six sigma metrics applications of quality control in clinical biochemistry laboratory

Abstract

Errors in clinical biochemistry laboratory are mainly due to the poorly designed quality control system. Six sigma is an error detection method which is first implemented by Motorola Company. Sigma stands for standard deviation. This is used whenever an outcome of process has to be measured. A poor outcome means an error or defect. The main objective of this study was to calculate six sigma for chemistry parameters run on Cobas 6000, Roche Diagnostics. After consulting statistician, 14 months Internal Quality Control values and External Quality Assurance System values were extracted for clinical chemistry parameters. Using coefficient of variation, percentage of bias, total allowable error, six sigma were calculated for each parameters. This study showed that following parameters had six sigma above6: total protein, alanine transaminase, aspartate transaminase, alkaline phosphatase, total bilirubin, creatinine, high density cholesterol and triglycerides, six sigma 3-6: albumin, direct bilirubin, urea and total cholesterol and none had sigma values less than 3. To conclude six sigma values for clinical biochemistry laboratory indicates that the maintenance quality of the lab.