The Application of Analytical Period Six Sigma in Tumor Markers in Clinical Biochemistry Laboratory

Objective: Six Sigma Methodology is a quality management methodology that provides information on process performance, focuses on variables in the process, and is based on statistical calculations. Methods: In the present study, analytical period sigma scores in tumor markers were calculated by using monthly and cumulative quarterly data. The present study is the first study in which sigma scores calculated with different Total Allowable Error (TEa (%)) and bias (%) values are compared by using statistical tests and the frequency of six sigma application is discussed. Results: When it was examined whether there was a statistically significant difference between the sigma scores that were calculated according to the biases obtained from the Internal Quality Control (IQC) and External Quality Control (EQC) data, although there was a significant difference in the Alpha-Fetoprotein (AFP) and Cancer Antigen 15.3 (CA 15.3) tests, no significant difference was found in the other tests. When the sigma scores that were calculated according to the TEa (%) values determined by the reference institutions were analyzed statistically, it was found that different TEa (%) values caused significant differences in sigma scores. When the sigma scores obtained by months and cumulatively were examined, it was found that there were significant differences between the examined periods. Conclusions: As a conclusion, it is important to determine the optimal TEa (%) value in sigma score examinations and to monitor the quality by analyzing the sigma scores on a monthly basis in terms of the sustainability of the result quality of the tests and for the early detection of problems.