Abstract: ObjectiveTo study the application of six-sigma (6-sigma) measurement tool in the evaluation of the quality level to promote detections of 9 clinical laboratory tumor markers (TMs). MethodsThe data from internal quality control and external quality assessment in clinical laboratory were collected for the 9 TMs (β-HCG, CEA, beta CA125、CA153、 CA199、 AFP、 t-PSA、f-PSA and FERR ) in 2014 and 2015. Using the total allowable error (TEa) as the standard by Ministry of Health Examination Center TMs EQA, the 6-σ value and quality target index (Quality Goal, Index, QGI) of each item were calculated according to the formula (TEa = Bias / CV%). The Sigma value is divided into world class (σ≥6), excellent (5≤σ<6), good 4≤σ<5) critical (3≤σ<4), bad (2≤σ<3) and unacceptable (σ<2) . The quality improvement plan was designed according to QGI and improvement measures were implemented of TM whose σ did not reach the world-class. The rectification of TMs levels improvement of quality evaluation was compared. ResultThe sigma average quality level increased from 4.93(2014) to 6.34(2015), the world class item consists of 2 (11.1%) to 8 (44.4%), excellent level item was 6 (33.3%), good grade increased from 4 (22.2%) to 7 (38.9%), bu the critical item and non acceptance item decreased from 2 (22.2%) and and 1 (5.6%) to zero, respectively. ConclusionThe 6- sigma can evaluate the level of clinical of TMs quality detection precision, show the defects, provide clear direction for quality improvement, and improve the quality level of TMs test. It is an effective laboratory quality management tool.

Key words: Tumor, markers, Sigma, Analysis, quality