According to Merriam Webster, Validation and Quality Control are defined as such:
Validation: : an act, process, or instance of validating; especially, the determination of the degree of validity of a measuring device
Quality Control: an aggregate of activities (as design analysis and inspection for defects) designed to ensure adequate quality especially in manufactured products.
Both areas are immensely important whenever you discuss the work we perform in the forensic DNA arena; without having confidence in the products you’re purchasing and operating procedures you’re performing, how can you have confidence in the end result. We rely on validation to prove the parameters of our procedures are correct and allow us to be as scientifically concise while QC/QA that the equipment, reagents, buffers, plastics, and training is in fact working the way it should. However, what happens when we reach those gray areas; You purchase new 96 well plates for amplification and sequencing or your R squared value for your quantification is less than the acceptable range. It’s those questions that we will talk about a bit today in this post.
The evaluation of each “grey matter,” as it were, should be looked at in a different light. Our first will be the purchasing of new 96 well plates. Several driving factors are easily responsible for the acquisition: simply run out of your current stock, vendor no longer carries the product, better pricing through a different supplier, or poor product quality, pushing you towards a new supplier. The first of the factors, simply run out of stock, is a simple enough fix; normally laboratories have standing orders but that is also contingent upon it’s size and throughput. The other three factors pose an interesting dilemma: I’m no longer using the same plates, so does that mean I am not following my standard operating procedure? Short and simple answer: That’s not true. You continue as you normally did. The QA/QC processes that you have in place will ensure that your SOP will not be violated. The plate characteristics should be similar and therefore, acceptable if it passes those tests. Such parts of SOPS, like plastics, are interchangeable as long as the proper procedures are in place to show the same result will be obtained.
On the other hand, what happens if your R squared value is outside the acceptable range? I’ve run into this issue before and in our SOP, we had a statement, indicating our technical leader could approve the quantification; granted, I worked in data basing and quantification wasn’t completely necessary. Casework’s outlook is significantly different and should be evaluated while considering more factors. How’s this avoided? QA/QC measures. The constant freeze thaws and exposure of light to quantification primers can be damaging, so although the lot of reagents currently in use may have passed, they could expire at an expedited rate. As analysts we must be educated on the ways to keep our data quality high and reagents in functioning condition.
We see how quality control and validation support one another immensely; without quality control, our validations wouldn’t mean much of anything. Sure, we proved a method works and so do those arrangements of reagents/buffers, but if we weren’t sure whether our essentials functioned properly, we could have complete faith in our work.
That’s all for today; I’ll be back early next week, not completely sure what topic I’ll be discussing, but surely a good one.
V/R,
Eric
bioFORENSICS 