January 30, 2016
OK, I admit it I’m a little slow and behind the times. By looking at the email for the Feb. table of contents for Clinical Chemistry, I discovered online content that I never noticed – a section about “Pearls of Laboratory Medicine.”
After looking at a few of the ones supplied, I realized there was a lot more available by joining the Clinical Chemistry Training Council site.
Wow, I was impressed by the amount of available material. I may not agree with everything there – as always – but this looks like a valuable resource. And I like the fact that material is presented by slides and webcasts as well as more traditional means.
January 19, 2016
When the 2003 ISO standard for glucose meter performance was prepared, the regulatory affairs people of industry controlled the standard. The standard called for 95% of results above 75 mg/dL to be within a total error of ± 20%. The standard was said to be based on medical requirements – clearly it was not based on state of the art since glucose meters perform better.
A problem probably unforeseen by these regulatory people was that a bunch of new players entered the glucose meter market and of course had no trouble getting FDA approval – the FDA used the ISO standard in its approval process. The number of meter brands on the market grew from 32 in 2005 to 87 in 2014. And some of the new meters sold their strips at a much lower price than the major manufacturers. This caused the four major companies to lose some market share.
Industry still plays a dominant role in glucose meter standards, but it seems that the original regulatory affairs people are out. Now, industry is working with the Diabetes Technology Society to certify glucose meters under new performance standards. Thus, meters that have FDA approval will be tested according to the tighter 2013 ISO standard and only meters that pass will receive a seal of approval from the Diabetes Technology Society.
Klonoff DC, Lias C, Beck S Development of the Diabetes Technology Society Blood Glucose Monitor System Surveillance Protocol. J Diabetes Sci Technol, in press. available at http://dst.sagepub.com/content/early/2015/12/10/1932296815614587.full.pdf+html
January 2, 2016
A couple of entries ago, I mentioned an upcoming publication. It has now appeared in the J Diab Sci Techol ahead of print (subscription required).
Basically, each glucose meter result in the A zone of an error grid has its difference from reference squared and that value scaled ranging from 0 (result=reference) to 1 (result is on the A zone boundary). If the value is outside of the A zone no A zone Taguchi loss value is calculated. These “Taguchi loss” values are then averaged to give the average Taguchi loss (ATL). One can calculate the ATL for all zones, although I did not do this for the article.
The ATL represents a way to distinguish performance among different glucose meters with similar performance (most values in the A zone and no values beyond the B zone). I believe it is an improvement over the MARD statistic (mean absolute relative deviation).