Another question from our Cut your QC webinar:
Do accreditation bodies accept the Six Sigma metrics?
Let's start out by being clear: Six Sigma is NOT required by CLIA, CAP, JCI, or any other regulatory or accreditation system in the world, as far as we know. It is an option, not a mandate. Thus, it's not something that has to be accepted. But it should not contradict what regulations and accreditation requires.
On the other hand, if your laboratory has streamlined your QC operations through Westgard Sigma Rules, you may find that an inspector challenges your choices. The inspector may be expecting to see "normal" QC practices like the 1:2s rule on all tests, or Westgard Rules on all tests. The variability of QC designs may seem unnerving to the unpracticed eye.
But surprise and unfamiliarity are not justifications for citing non-conformances. They speak more about the inspector than the laboratory. The inspector might insist that certain QC rules and common behaviors be implemented, but there is no language in regulation or accreditation requirements that will back them up. So if the inspector challenges you on the choices you've made wit your QC, you should challenge the inspector right back to prove that there is some specific clause that prevents your choices.
The truth is that every regulatory or accreditation requirement for QC sets a very low bar. Essentially, all you need to show is a graph with line and dots. Got some horizontal lines? Check. Plotted some dots above and below those lines? Check. Congratulations, you have passed the QC portion of your inspection. That's slightly reductive but essentially true. There are no mandatory QC rules in any regulation. The regulations just say that a lab should "do" QC without any specifics on "how much" QC is appropriate. That's why labs can get away with using 1:2s on all their tests. It's a tremendously wasteful practice but it is compliant, since compliance for QC is an extremely low bar.
Remember, regulations are typically the floor on laboratory behavior, the minimum that you should do to stay out of jail. Excellence, and Six Sigma, is about aiming for the ceiling not the floor, and even to continuously push the ceiling higher.