Molecular Diagnostic QC?

Originally posted on October 3rd, 2006.

We don't often talk about molecular diagnostics and quality control. Getting a handle on the "usual" tests in chemistry, hematology, etc., has been a tough enough job. But the field of molecular diagnostics is expanding rapidly. And quality for those tests is going to be just as important, if not more important in the future.

 
Here's a simple description of a quality issue in molecular diagnostics testing: picture a tube or a well, or in the case of multiplex testing, several tubes or an array of wells. Each entity contains several different reactions to determine the presence or absence of specific genetic sequences. The current practice is to test just one or two of the reactions for quality control. And even if the QC reaction has different detection probes or primers than all the others reactions, if the value for the control is "in", it is assumed that all of the other results are valid.

 
This has been the state of the art for a limited number of assays and it seems risky at best. But these array tests are growing by orders of magnitude. Where now there may be under 100 tests in an array, new ones that will have several hundred, maybe a thousand, are under development. The validity of the current state of the art for QC, that is, to rely on testing just a small sampling of the different reactions, needs to be examined.

 
Dr. Clark Rundell, from Maine Molecular Diagnostics, is at the forefront of the QC field for molecular diagnostics. He recently wrote an article for MLO on the "QC challenges for molecular testing." It's worth a look - this is going to be one of the key early articles for this important area.

http://www.mlo-online.com/articles/0506/0506special_feature.pdf