New Download: Sigma-Metrics Tool (and audioconference presentation)
On September 4th, 2008, Dr. Westgard spoke as part of the AACC audioconference on "New Directions in Laboratory QC" - which was subsequently quoted in the Clin Lab News article on Risk and CLIA. We are pleased to make available Dr. Westgard's complete presentation, as well as two Sigma-metrics Charts and instructions on how to use them in QC Design.
Westgard Sigma Analysis: A new direct HbA1c Method
At the 2008 AACC/ASCLS convention, a poster was presented for a new direct enzymatic assay for %HbA1c. How does it stack up against HPLC and immunoassay methods? How do you judge a method when you've got multiple comparison methods and multiple quality requirements?
Interview: Dr. R. Neill Carey (A brief introduction to EP 15)
We were fortunate to get R. Neill Carey, PhD, the chair of the CLSI EP 15 committee, to present and
explain that new standard at the Chicago Method Validation workshop. He also contributed a chapter to the new Basic Method Validation manual on the same topic. But for those who have never heard of EP 15 before, we conducted a short interview with Dr. Carey. This short introduction to EP 15 may pique your interest in this new guideline.
Thinking about Three Sigma: 2 thoughts on troublesome performance
In a previous lesson, we discussed some possible actions to take when the Sigma-metric for a method is higher than Six. But what about those methods with low Sigma-metrics? What do you do when Sigma analysis delivers bad news?
Posted by Sten Westgard
One of the highlights for me of the AACC convention in Washington, DC, was my inclusion in a poster that analyzed the method performance of the Abbott Architect c8000. I'm pictured here with fellow authors (left to right) Gene Osikowicz, Charles Wilson, and John Baker (lead author). They deserve most of the credit for the work of collecting the data.
The poster can be viewed here and the QC application on Westgard Web can be viewed here. -----
Posted by Sten Westgard, MS
I just wanted to share some pictures of a trip taken back in late April.
The Asian Society of Continuing Medical Education was kind enough to invite me to present in a workshop titled "Assuring Quality, Standardization, and Efficiency in the Laboratory 2012" In Delhi and Mumbai.
Group picture, Mumbai
More pictures, after the jump.
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Posted by Sten Westgard, MS
Posted by Sten Westgard, MS
Here's a range of statistics describing the performance of a glucose method. Try to pick: Which one has acceptable performance?
- method with combined uncertainty 3.69%
- method with combined uncertainty 6.79%
- method with expanded uncertainty 7.38%
- method with expanded uncertainty 13.58%
- method with 3.78 Sigma
Which method would you pick?
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Posted by Sten Westgard, MS
In the recent issue of Clinical Chemistry, an editorial reviews the current state of Vitamin D testing: "There is common agreement that 25-OHD is a 'difficult' analyte."
25-Hydroxyvitamin D: A Difficult Analyte, Graham D. Carter, Clin Chem 58:3; 486-488 (2012).
At the same time, the editorial notes that marked process is being made:
"Nevertheless, results submitted to the international Vitamin D External Quality Assessment (DEQAS) have shown a gradual reduction in interlaboratory imprecision (CV) in recent years - from >30% in 1995 to 15% in 2011."
The question is, is that reduction in imprecision good enough? Or is the quality required by Vitamin D still too "difficult"?
More after the jump...
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Posted by Sten Westgard, MS
In the December 2011 issue of Point of Care journal, an interesting study was published:
Preanalytical Errors in Point-of-Care Testing: Auditing Error of Patient Identification in the Use of Blood Gas Analyzers, Natalie A Smith, David G Housley, Danielle B. Freedman, Point of Care, Volume 10: Number 4, December 2011.
The study looked at patient identification errors on a blood gas analyzer in various departments in a hospital. Bearing in mind that this is just one type of pre-analytical error, what do you think the rate was? Given around 100,000 tests, what would you guess as the number of defects?
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Posted by Sten Westgard, MS
Posted by Sten Westgard, MS
Posted by Sten Westgard, MS
One more shot at error rates! At the IFCC Berlin conference, there was an intriguing abstract about the use of Quality Design/Planning tools in the laboratory:
Abstract #1062: Efficiency of Analytical Qualit yControl with Various Quality Planning Tools in Thai Clinical Laboratory. K. Sirisali, S. Manochiopinj, S. Sirisali.
How high do you think out-of-control rates can go?
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Posted by Sten Westgard, MS
Earlier we discussed error rate issues at the Point-of-Care. But we didn't want to leave the "regular" laboratory out of the fun, so here's a study of error rates that came out in 2010:
Evaluation of errors in a clinical laboratory: a one-year experience, Goswami B, Singh B, Chawla R, Mallika V, CCLM 2010;48(1):63-66.
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A new study in Clinical Chemistry investigated the errors rates for Point-of-Care (POC) devices:
Can you guess what the error rates were?
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Posted by Sten Westgard, MS
[This picture is actually from Curitiba, Brazil, the SBAC conference back in late June, at a lecture I gave there on Sigma-metrics. I don't have a picture of my lecture from Atlanta, but there is video.]
I gave a short booth presentation on Best Practices for Sigma-metrics at the Abbott Diagnostics booth during the AACC/ASCLS convention. This is now available online for those interested.
The link, after the jump.
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Posted by Sten Westgard, MS
It's that time of year again, where the usual and not-so-usual suspects of the laboratory world gather and discuss science - mixed in with a healthy dose of commerce. We have just returned (and are still recovering from) the annual AACC/ASCLS meeting in Atlanta, Georgia.
James O. Westgard at the Westgard QC booth for the 2011 AACC/ASCLS exhibition
More pictures and details of the convention after the jump...
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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.