Posted by Sten Westgard, MS
The second and third days of the Westgard Workshops 2011 focused on Six Sigma Risk Analysis - quantiative, data-driven Risk Management. CLSI will soon be issuing official guidelines on Risk Analysis for QC (the proposed version of EP23 is available, but the final accepted version is not. The CLSI EP23 guideline is expected to be approved by the end of the summer). But there's no need to wait for CLSI to do Risk Analysis. There are many existing resources for laboratories to utilize and start right now.
Tina Krenc, an expert in FMEA (Failure Mode and Effects Analysis), leads a group activity on the use of FMEA for laboratory processes
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Posted by Sten Westgard, MS
The Westgard Workshops 2011 were held in Madison, Wisconsin last week, June 1st through 3rd.
Dr. Westgard discusses a question with participants
The topic for the first day was Six Sigma Metrics and Tools. Six Sigma is well known even in healthcare. We did our first Six Sigma workshop about a decade ago. But some of the calculations and implications of Sigma-metrics, particularly for analytical performance, remain less well known. We covered not only the calculations but also the outcomes - how it can improve QC, reduce repeats, increase error detection, and provide better reporting advice to clinicians.
But even beyond these benefits of Sigma-metrics, there's a simple advantage to using the Sigma scale when discussing errors.
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Posted by Sten Westgard, MS
We live in an era of diminished resources, particularly in healthcare, particularly in the laboratory, and particularly for education and training. The training budgets for labs have been shrinking and shrinking over the years, even as the need for skilled technologists has increased.
Educational institutions have not been able to provide enough (high quality, lost cost) training to fill the need. So the manufacturers and vendors have stepped into this gap, supporting the educational needs of their customers.
Westgard Workshops 2011 could not have been mounted without the generous educational help of our gold sponsors, Bio-Rad Laboratories and Abbott Diagnostics. Randox Laboratories also stepped up and provided a premier sponsorship, which helped us immensely.
Dr. James Westgard, pictured here with representatives of the Premier Workshop Sponsor, Randox Laboratories. At Left, Vinay Naik, National Account Manager, who introduced the workshops. Also pictured here is Lynsey Adams, Scientific Writer.
After the break, you can hear the Westgard Workshops Introduction from Randox...
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Posted by Sten Westgard, MS
Posted by Sten Westgard, MS
An interesting question came in through email (
"1. Can we apply Westgard multirules to hematology control?
2. I read in one paper that the hematology control range is calculated as mean +/- 2.5 SD, is this correct and if not how can I calculate own laboratory hematology control range?"
The answer, after the jump...
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Posted by Sten Westgard, MS
We got an excellent question the other day via email:
I have heard the term "Within QC" and "Across QC"
used, but what do these refer to specifically and
where can I find more information about what is
meant by those terms? I was not able to find this
information, but laboratory leadership staff said
that "Within QC" referred to assessing multi-rules
"within QC level and across QC runs", and that
"Across Qc" referred to assessing multi-rules
"looking at both QC levels, can be within same run
or back-to-back runs".
A lab has the following multi-rules; "Within QC"
1:3s, 1 QC result outside 3sd; 2:2s, 2 consecutive
QC results outside 2sd on the same side of the mean;
4s, 2 consecutive Qc results differ by more than
4sd; and 1:2s, 1 Qc result outside 2sd and within 3.
(1:2s is used as a warning rule, the others as
rejection rules). The rules for "Across Qc" are as
follows; 2:2s, 2 consecutive Qc results (1 each
multiple levels) are outside of 2sd; and 4s, 2 Qc
results (one of each multiple levels) are >4sd
apart. These are both rejection rules. These
multi-rules are used to assess all tests in a
chemistry lab; the majority of tests are assessed
with 2 levels of Qc, a few use 3 levels of Qc.
The situation arose where QC results on one day for
a cancer antigen were the following:
Day 1A:
Level 1 -Within 2sd, acceptable
Level 2 -1:2s, run was accepted as only the warning
rule 1:2s was encountered.
The next day the results were as follows:
Day 2A:
Level 1 -1:2s
Level 2 -Within 2sd
Leadership said run should not be accepted,
violating the "across" 2:2s rule.
However, leadership said the inverse situation would
have been acceptable as *consecutive* data points
did not violate the "across" 2:2s rule, i.e.
Day 1B:
Level 1 1:2s
Level 2 within 2sd
Day 2B:
Level 1 within 2sd
Level 2 1:2s
In the A group, because Level 2 is outside of 2s,
and the very next data point (Level 1 from the next
day) is also out 2s, the run is unacceptable and
should be rejected. In Group B, since consecutive
data points are okay the run is acceptable.
Is this a correct approach? Is it correct to reject
group A (Day 1A and 2A) and not reject group B (Day
1B and 2B)? Do these multi-rules as outlined and
implemented detect some unacceptable variation in
group A that does not exist in group B? Thank you
for any clarification.
So what's the answer? Are scenarios A and B fundamentally different? More after the jump.
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Posted by Sten Westgard, MS
Posted by Sten Westgard, MS
Posted by Sten Westgard, MS
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 = 224
Actual 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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Posted by Sten Westgard, MS
(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:
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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