Silver nanoparticles ( AgNP) , the metallic silver par-ticles with the diameter of 1 ~100 nm are now widely used in many fields. Many researches show that the smaller size of Ag-NP, the stronger toxicity it shows. Generally speaking, AgNP with 20 nm shows strongest toxicity. After entering the body, they are distributed in different organs in the body, and the dis-tribution in the kidney shows a certain gender difference. They also produce some toxic effects after entering body organs. AgNP often exhibit dose effect on the toxicity in vitro cells,while in vivo experiments, their toxic effects change with the different objects and ways of acting. In addition, AgNP can produce toxic effects on reproduction, and may cause parental reproductive activity to deteriorate, and pass the toxic effects to offspring through the placenta to exert a negative influence on the growth and develop-ment of the offspring. The toxicity mechanisms of AgNP are oxi-dative stress injury caused by producing free radicals;metabolic disorders caused by reducing of drug metabolic enzyme activity;and also related gene expression defects and certain molecules, such as transcription factor NF-E2-related factor 2(Nrf2) prote-ase caused by abnormal expression. In short, AgNP can be toxic to organisms, and we must evaluate their biological safety when we use it, to minimize or even avoid the danger it brings about.

Objective To improve the quality of clinical biochemistry laboratory by quality indicators of pre-analytical,analytical,post-analytical phase and the whole process.Methods Analytical Phase:The Sigma values of items were calculated,applying the equation Sigma =(TEa％-Bias％)/CV％.Total allowable error (TEa) is from analyticalal specification defined in WS/T403-2012 of China,Bias％ is from the evaluation results of National Center for Clinical Laboratory (NCCL) trueness verification PT series and CV％ is from internal quality control data during the last 6 months in our lab.Normalized Sigma metrics plot was made to evaluate the analysis performance and the quality control strategies were designed accordingly.The quality goal indexes (QGI) were also calculated to propose improvement measures for items below 6 Sigma.Quality indicators of pre-,post-analytical and whole analytical phase,such as quality of specimen,critical value notification,critical value notification in time,TAT of hs-cTnT,TAT of emergency biochemical items,rewrite of laboratory reports and unacceptable performance in EQA-PT were measured in Sigma metrics too.The Sigma metrics changes before and after taking improvement measures were compared to conform the effectiveness.Results The average Sigma value of 17 biochemical tests was 5.29,of which 8 items (UA,K,ALP,CK,AMY,AST,TG,Na) achieved excellent to world class level (≥ 5 Sigma),6 items (LDH,Cre,TC,ALT,Mg,Glu) achieved marginal to good level (5 ＞ Sigma ≥ 3),BUN performed poorly (3 ＞ Sigma ≥ 2),Ca,TP performed unacceptably (Sigma ＜ 2) with serious quality defects.The Sigma values of unacceptable specimen,critical value notification,critical value notification in time,unacceptable turn around time (TAT) of hs-cTnT,unacceptable turn around time (TAT) of emergency biochemical items,rewrite of laboratory reports,unacceptable performance in EQA-PT were 4.17,3.60,2.75,1.72,3.27,4.52,3.33 respectively,rising to 4.30,4.30,2.90,2.45,3.75,4.80,3.60 accordingly after improvement.Conclusions Sigma metrics is potentially an ideal approach for clinical biochemistry laboratories management,which is helpful to find out problems,put forward improvement measures,and confirm the effectiveness,so as to achieve the purpose of continuous quality improvement.