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.
Let's take a few of Mr. Midyett's points in turn:
"At some point between the early days of QC and today, a 'one size fits all' mentality in regard to QC began to take hold. This is cousin to the popular 'zero tolerance' attitude, as in 'no test shall go uncontrolled.'” This is the typical compliance approach taken by most laboratories. They run QC in a blanket fashion, applying the same QC procedure to all tests, without taking into account the specific circumstances of each assay, resulting in Quality Theater (QT), or Arbitrary Control (AC), but definitely not QC. Interestingly, this policy is not required by law. The law says you should do some amount of QC on each test, and CLIA sets a minimum default procedure. What has happened is that laboratories took that CLIA minimum policy and applied it to all tests as their blanket policy (effectively their maximum QC effort). And then this became the norm. Both regulators and laboratories have some share of the blame in this. Regulators and accreditors can help by encouraging better policies in the laboratory - raising the bar above mere compliance, to true quality systems.
"[T]here should be some agreement about exactly what the particular QC is monitoring. If QC is simply 'out,' but does not lead to any corrective action other than trying a new control, then it’s time to rethink if it is actually QC. I have no doubt someone can come up with a simple statistical tool or formula, or even a common sense guideline, that could help determine the efficacy of a QC procedure." There is a way to quantitatively determine the appropriate QC procedure for a test. It involves such tools as the Critical-Error graph, the OPSpecs chart, and the Sigma-metric. Some of these tools have been around for several decades. They allow you to determine the appropriate QC procedure for a test - and also to determine the performance of a QC procedure and its ability to detect medically important errors.
"Empty QC never detects errors in the system." True, if the QC procedure is performed without proper design, taking into account the quality requirement, the imprecision, and the bias.
Luckily for Mr. Midyett, and all the laboratories suffing similar problems, there are solutions: QC can be "right-sized" using QC design and Sigma-metric tools. And for tests that are difficult to QC, labs in the US will soon have the option of adopting Risk QC and IQCPs (individualized quality control plans) that will provide a customized complement to the traditional statistical QC approach.
Here are jus a few articles on Westgard Web that reinforce and explore the same topics as Mr. Midyett's:
- "But is it really out?"
- The QC we really do
- Re-Emerging issues in QC Today
- Would you drive your car the way you run your QC?
- Quality control vs. Quality Compliance: What's SAFE?
So is QC empty? I prefer to think it's more than half-full. There are a lot of tests where QC is necessary and useful. There are a few tests where QC is a challenge and needs some modification. And finally, there are many, many labs where QC is not being performed in a way that is helpful to the laboratorian, clinician, and patient. Mr. Midyett's essay reminds us that it's up to all of us to fix that.