Tools, Technologies and Training for Healthcare Laboratories

Sigma-metrics of some Chemistry Instruments in China

Recently, with the help of some Chinese laboratorians, we translated the studies of Sigma-metrics of several chemistry instruments.

Sigma-metrics of some Chemistry Instruments in China

March 2017
Sten Westgard, MS

[Note: This QC application is an extension of the lesson From Method Validation to Six Sigma: Translating Method Performance Claims into Sigma Metrics. This article assumes that you have read that lesson first, and that you are also familiar with the concepts of QC Design, Method Validation, and Six Sigma. If you aren't, follow the link provided.]

For years, I have been looking at the growing body of Chinese scientific literature in laboratory medicine with a bit of envy. While often the abstracts and titles are in English, the main texts are in Chinese. So it was with grateful thanks I was aided by several laboratorians in translating some of these articles. In China in particular, a growing body of articles on Sigma-metrics has been growing.

The evaluation on the performance and etymologies of Beckman AU680 biochemical analyser Li Xin, Zhou Chun-jie, Wu Jun-mei, Liu Feng-xia (The Clinical Laboratory of Jiangjin District Chinese Medicine Hospital, Chongqing...China), Lab Med Clin, September 2012, Vol. 9, No.18.

From this we're able to generate a Sigma Decision Chart on 7 assays (ALP, AST, Total Bilirubin, Creatinine, Potassium, Sodium, and Chloride):

 Chinese lab medicine 2012 AU680 chemistry NMEDX

There's a wide spread of performance here, not necessarily what we expect of the AU680. Other examples of the AU680 performance have demonstrated better Sigma-metrics.

Then another instrument study was in the literature - this time the instrument identity is kept basically anonymous.

Application of allowable total error in sigma metrics for assessing the analytical quality of clinical chemistry determination, Zhang Lu, Wang, Wei, Wang Zhiguo, Laboratory Medicine, Setpemebr 2015, Vol 30, No.9.

 Chinese Laboratory Medicine 2015 anonymous chemistry NMEDX

Nearly 50% of the instrument performance is at 3 Sigma or worse.

Now this instrument  performance is also not so good. It is tempting to characterize this as typical performance of instruments in China, however, we have very different examples of performance from laboratories in the Sigma VP program. So we see there is actually a wide disparity present. There are laboratories in China with world class quality as well as laboratories with poor quality. Not so different from the rest of the world, then.