Posted by Sten Westgard, MS
"We have a department supervisor that instructs the techs to delete (not omit) qc values outside of three s.d..Is there a specific CLIA rule against this? Where I come from, deleting qc values is wrong."
What do you think? The answer, after the jump...
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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...
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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
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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...
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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...
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Posted by Sten Westgard, MS
Last month I was fortunate enough to attend the INTERCAL meeting in Lima, Peru, hosted by SIMED.