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. -----

By Sten Westgard, MS

Posted by Sten Westgard

This month, Dr. Westgard was teaching his spring semester class for the University of Wisconsin Medical Technology school. He likes to use recently published papers in the scientific literature as a way to relate his lessons to things happening in the "real world" of the laboratory.

This semester, he has written up a number of lessons covering HbA1c methods, performance, and quality requirements based on the article in Clinical Chemistry, Few Point-of-Care Hemoglobin A1c Assay Methods Meet Clinical Needs, by David E. Bruns1 and James C. Boyd and a study by Lenters-Westra and Slingerland (Six out of eight hemoglobin A1c point-of care instruments do not meet the generally accepted analytical performance criteria. Clin Chem 2010;56:44 –52.)

For your convenience, here are the lessons in order...

Posted by Sten Westgard, MS

Another question coming in from one of our website members:

Could you give me some suggestions on establishing QC ranges for unassayed chem. Controls?

We currently use [Brand X] unassayed chem controls (much less in cost than assayed controls) for some of our chemistry analytes.

For these controls, we are provided a “target mean” and a range.

Occasionally, our established mean (i.e. n=30) for a new lot  is outside of the range provided for “target mean” provided by manufacturer.

Could you suggest guidelines for acceptance of lab established means for unassayed controls? 

Obviously, I would like to know how far from the “target mean” could the new lab established mean be?

The answer, following the jump...

Posted by Sten Westgard, MS

Recently, a user submitted a question about the mandatory use of the 10_x rule on chemistry analytes as mandated by ISO 15189 through NABL:

"Specific criteria of accreditation of NABL India (for ISO 15189) say that 10x should be considered as a violation for clinical chemistry  and Immunoassay parameters. However we understand that Westgard rules consider it as a warning only. Please advise."

So, the central question is, does ISO 15189 mandate the use of the 10_x control rule?

Posted by Sten Westgard, MS

We got the following question emailed to the website recently:

Greetings, I was [wondering] if the following case represents [violation] of 4 1s rule?

Control (A) point 1= EXCEEDS 2 SD /-2 SD lines >> warning

Control (A) point 2= WITHIN 2 SD/-2 SD lines >> accepted

Control (A) point 3= EXCEEDS 2 SD /-2 SD lines >> warning

Control (A) point 4= WITHIN 2 SD/-2 SD lines >> rejection

all the point[s] on the same side of the mean.

What do you think? The answer, after the jump

Posted by Sten Westgard, MS

Posted by Sten Westgard, MS

An interesting question came from one of our readers, about how to interpret certain outliers.

So let's take one example, just two control values, expressed in z-scores. If the low control is -3.1  and the high control is + 2.3, which rule is violated? the 1:3s rule? The R:4s rule? Both?

An answer, after the jump...

Posted by Sten Westgard, MS

An important new study was published in the International Journal of Laboratory Hematology, on the QC practices of coagulation laboratories.

But here's a question for you: of all these activities, how many of them occur greater than 90% of the time - and which one doesn't?

• Repeat the QC, and if it passes, report results
• Open [and run] new QC
• Look for trending
• Discontinue testing until controls are within limits
• Repeat all patient samples from the last acceptable QC

To find out which one of the activities occurs at a frequency not like the others, follow the jump...

Posted by Sten Westgard, MS

Visit our booth or better yet Thermo Scientific's booth for a nice take-home from Chicago.

Posted by Sten Westgard, MS

Posted by Sten Westgard, MS

Posted by Sten Westgard, MS

Posted by Sten Westgard, MS

Posted by Sten Westgard, MLO

In the November 2012 MLO magazine there is an intriguing article by Roy Midyett, a hematology supervisor, titled "Empty QC"

Here's how Mr. Midyett defines "Empty QC":

"Empty QC is any nominal QC that does not give techs performing the test any more confidence than they would have without the QC, and has by logic or experience, no influence on the reporting of the test."

Is Mr. Midyett correct? Have our QC procedures become meaningless gestures? More after the jump.

Posted by Sten Westgard, MS

So here's a Normalized Method Decision chart for a cholesterol method.

Which method would you choose?

Posted by Sten Westgard, MS