Abstract:?Objective?To analyze the quality control data of tumor markers by using Sigma (σ) measurement items, evaluate its analytical performance, design the methods for quality control and guide continuous quality improvement.?Methods?The data of internal and external quality assessments of 10 tumor markers participating in the external quality assessment of Clinical Laboratory Center of National Health Commission were collected in The First Affiliated Hospital of Xi 'an Medical College during the period of 2018 and 2019, including AFP, CEA, CA125, CA199, CA153, TPSA, fPSA, FERR(ferritin), β-hCG and β2-MG(microglobulin). According to the total allowable error (TEa) standard of the Clinical Laboratory Center of National Health Commission, the 6σ formula was used to calculate the σ value of the test items, evaluate the analytical performance of the test items, design the quality control method, calculate the quality objective index (QGI) of the test items, analyze the main causes of poor performance by using fishbone diagram, and propose a the priority improvement scheme.?Results?The results of 2018 showed that, the average value of σ among the 10 tumor markers was 4.25, including σ≥6 in 2 items, 5≤σ<6 in 5 items, 4≤σ<5 in 4 items of, 3≤σ<4 in 7 items, and 2≤σ<3 in 2 items. According to the QGI value, the precisions of 7 items were needed to improve, including AFP, CA125, CA199, CA153, FERR, β-HCG and β2-MG. The accuracies of 3 items were needed to improve, namely CEA, t-PSA and f-PSA. By continuous improvement, the average value of σ in 2019 was 6.58, including 16 iterms with σ≥6, 3 iterms with 5≤σ<6, and 1 item with 4≤σ<5. Compared with the σ value of 2018, the proportion of iterms with world-class levels increased significantly (P<0.05).?Conclusion?Six Sigma quality management should be an effective management tool for laboratory quality control, which may evaluate the performance of test items and guide continuous quality improvement.