Posted by Sten Westgard, MS
A recent question came in from a technical support consultant for a major diagnostic manufacturer:
"It is for Free T4 analyte. Customer [has] establihed a QC range after 20 QC runs. Mean and SD were derived from 20 runs and %CV achieved from 20 runs is 1.2%. Allowable interassay precision criteria according to CLIA is 6%.
"Now when customer [applies] Mean and SD according to the established range many...times they face QC rules violations of 41s and 10x.
"So can you please suggest, when the SD is too narrow is it necessary to apply these two rules to immunoassays?"
What's your guess? I'll take a stab at an answer, after the jump.
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Posted by Sten Westgard, MS
I came across a very valuable paper in Clinica Chimica Acta on the stability of hematology controls for MCV. (Some of you are already guessing what this is going to be about...)
If you take a hematology control, how many SDs should you expect to see it shift at week 5 of use versus the first week of use? In other words, what is the SDI you should expect?
1 SDI
2 SDI
3 SDI
4 SDI
5 SDI
higher than 5 SDI
The answer, after the jump...
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Posted by Sten Westgard, MS
Here's what's new on Westgard Web in December...
Posted by Sten Westgard, MS
A recent study reported on the error rates in an inpatient Iranian laboratory. If we pick just the Procedure error rate, which included internal control failure, external control failure, typing error, incorrect released results, and others, what do you think the rate was?
about 3 Sigma
about 4 Sigma
about 5 Sigma
about 6 Sigma
The answer, after the jump...
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Posted by Sten Westgard, MS
According to a recent CAP Q-Probe, approximately how many glucose tests are being bracketed by QC events?
Is it
5,000 tests between QC runs
500 tests between QC runs
50 tests between QC runs
5 tests between QC runs
The answer, after the jump
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