What's New on Westgard Web: February 2012

Posted by Sten Westgard, MS

UNCERTAINTY: IT'S OFFICIAL

CLSI has issued its C51A document, which officially brings the ISO
metrology concepts of uncertainty to the US. Dr. Westgard explores the
document in detail, explaining how uncertainty will impact the
laboratory.

ISO uncertainty: not just for metrologists anymore
 https://westgard.com/clsi-c51.htm

SIGMA-METRIC PILOT STUDY IN INDIA

A 2011 study from the Indian Journal of Clinical Biochemistry examined
the performance of a clinical chemistry instrument. We review the data
and provide graphic charts.

Do instruments perform differently in India?
 https://westgard.com/india-lab-sigma.htm

IS THERE A NEED FOR A MEAN RULE? QC DESIGN FOR A PHOSPHORUS METHOD

One question we get frequently is, "Do the violation of the 10x rule
mean anything for test X?" At the heart of this question is another
question: what QC rules are actually necessary to assure the quality of
a method? With the help of user-submitted data, we take a closer look
at this question.

What's the meaning of a mean rule violation?
 https://westgard.com/need-mean-rule.htm

Related Q&A on the blog: Are mean rules mandatory?
 http://james.westgard.com/the_westgard_rules/2012/02/mean-rule-can-iso-be-wrong.html

MORE QUALITY REQUIREMENTS: MINIMUM SPECIFICATIONS FOR ALLOWABLE TOTAL
ERROR

Last month, we had the privilege of publishing the latest database on
within-subject biologic variation in analytes, from the Ricos et al
group. In previous years, we have only posted the desirable
specifications. This year we are expanding to show the whole set: not
only desirable specifications but also optimal and minimum
specifications. How good should we be? How low can we go? These new
tables help provide some guidance.

Optimal specifications for allowable total error
 https://westgard.com/optimal-biodatabase1htm.htm

Minimum specifications for allowable total error
 https://westgard.com/minimum-biodatabase1.htm