I need to speak up due to a summary made by Jim Westgard regarding my talk in the Quality in the Spotlight Conference from Antwerp.
- Jim referred to my presentation where I said the “total” in total analytical error left out too many errors. Jim suggested I referred to pre-pre-analytical errors among others but I definitely stated that analytical errors are also left out of the Westgard total error model. I’m not sure what a pre- pre- analytical error is anyway. It is true that there are some rare errors that will be very difficult for a lab to detect, such as software errors or manufacturing mistakes.
- Jim suggested that total analytical error (e.g., the Westgard model) is broader than separate estimates of precision and bias. I don’t see how.
- He said that labs don’t want more complex equations / models. I’m sure this is true but what our company did was even simpler than the Westgard model – we simply looked at the difference from candidate minus the comparison method for all data. There were no models. The data were ranked to show the error limits achieved by 95% and 100% of the data. Not being constrained by models makes things simple.
- Jim said that ISO 15189 does not require uncertainty measurement that includes pre- and post- analytical error. That may be, but it doesn’t make it right.