Posted by Sten Westgard, MS
Here's a question that came in about setting the control limits (or range) for a test:
"for some assays we're using this formula: actual SD * 3 and then divided by 2 plus or minus the mean is this acceptable or not because when we use that give us abit wider range than using the mean plus minus 2SD."
When we asked for an example, we got this data:
Manufacturer Data: SD = 22.5, Mean = 224Actual Data: SD = 8.79, Mean = 223
"We're multiplying ourSD (8.79) by 3 and then we divide it by 2 to give us the new SD which is 13 (8.79*3/2 = 13). Then we multiply this new SD 13 by 2 to give us the real 2 SD range which is 26. So our range is now 197 - 249. Are we following the right way or not?"
The answer, after the jump...
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(Or, if only some surveys are based on accuracy, then what are the other surveys based on?)
Posted by Sten Westgard, MS
There's an article that appeared in the October 2010 issue of CAP Today that probably didn't get enough attention. It covers a subject that's been gnawing at us for a while:
Accuracy-based Surveys carve higher QA Profile, by Anne Paxton
For those of you who thought all proficiency testing was "accuracy-based", this article may give you a bit of a shock. In fact, most PT surveys - indeed most EQA programs and even peer-group programs - are not based in accuracy. Instead, those surveys are only based on "consensus."
What's the difference, What does it mean - and how did it come to be this way?
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Posted by Sten Westgard, MS
Westgard QC is proud to announce 2 new public workshops to be held this year:
Six Sigma Tools and Metrics, June 1st
Risk Assessment Guidelines and QC Plans, June 2nd-3rd
Both workshops will be held at the DoubleTree Hotel in Madison, Wisconsin.
For more than a decade, the Westgard Workshops have provided in-depth training that can't be found at other conferences. If you want to be more than an anonymous seat in a cavernous hall... If you want to learn whether or not the latest management fad has any real applications in laboratories... If you want honest assessments instead of equivocal statements... If you care more about practical tools than precious theory... You need to attend the Westgard Workshops.
More details on the workshops after the jump...
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Posted by Sten Westgard, MS
Earlier, we posted an article on the website with a darkly humorous take on the passing of the CLSI EP22 guideline, which voted itself out of existence in late 2010. Other websites have also noted its passing.
But it's worthwhile to take a moment to discuss, in all seriousness, where we are with Risk Information, Risk Management, "Equivalent QC", and the CLIA Final Rules. How did we get here? What drove us to this state? Where are we going next?
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Here's a question from a website visitor regarding assigning a mean value for a new QC material with the following assumptions: "1. The analyte reports out as a whole number. 2. The results of calculations on 20 replicate samples are; A. Mean = 10.5 B. SD = 0.5 C. 2 SD Range = 9.5 - 11.5 D. 95% Confidence Interval = 10.3 - 10.7 E. CV% = 4.9 The question is "what to set the mean at?" One camp contends that the mean of 10.5 should be used, even though no result will ever "hit" the mean. The other camp states that the mean should be set to 10 or 11 regardless of whether or not a LJ shows bias, or even 10x failure. "
Answer after the fold.
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We see the Bail Outs of the bankers and wall street. We see the cutbacks and austerity of governments in Greece and Ireland as their governments struggle to make good on the debts run up by their out-of-control banks.Private risks made into Public losses.
But is the laboratory immune from the problem of "Too Big to Fail"?
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Posted by Sten Westgard, MS
The National Oil Spill Commission released a preliminary chapter of its report today. This is the commission charged with finding out what went wrong with the Deepwater Horizon / Macondo oil rig in the Gulf of Mexico that blew up in 2010 and spilled 4 million barrels of oil and killed 11 workers.
Whenever there are big stories in the media, we like to take a look at them to see if we can learn anything, find any connection between the disaster and our own situation in the medical laboratory community. But from a distance, it's hard to see any similarities between oil rigs and labs, right?
Right?
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Posted by Sten Westgard, MS
This question comes to us from a CLS student in Texas:
"I was hoping that someone might be able to answer a question that is causing me and some of my classmates some confusion. There is some confusion when you are plotting your QC chart and all your values are a whole number. Would you keep you SD as a whole number or make it to one decimal place? And if you did make it to one decimal place, would you be making your SD more accurate that your original value?"
Answer after the jump...
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