Basic QC Practices
Putting Quality into Quality Control
Many laboratories and manufacturers say that they "do" quality control - but can't explain what level of quality they're acheiving. The term "Quality Control" is much-abused. In many cases, Dr. Westgard explains that what laboratories are actually performing is arbitrary control, not quality control. How do we put the quality back into quality control? Reading this essay is a good start.
A MESSAGE FROM JAMES O. WESTGARD, PH.D.
IN QUALITY CONTROL
We seem to be at an impass in dealing with the issue of quality in laboratory testing. Like it or not, quality is an issue because the public perceives laboratory test results are not as reliable as they should be. CLIA-88 provides evidence of the public’s concern.
Laboratories, manufacturers, and the government all are hoping the issue will be dealt with and the public’s concern will go away. The government, through its rules to implement CLIA, has required that laboratories improve their process for managing quality and has specified new QC guidelines that are to be followed. Laboratories must devise QC procedures that meet these requirements or follow manufacturer’s QC instructions that have been cleared by FDA. FDA has drafted guidelines for obtaining QC clearance, but has indicated it does not have the resources to implement the clearance process. Knowing this, manufacturers have proceeded slowly, assuming that the implementation deadlines will be delayed. Meanwhile, laboratories are expecting they can follow current manufacturer’s recommendations until new QC procedures are cleared. The net result is that little is happening to improve the quality of laboratory testing, in spite of the enormous time and effort being expended discussing, worrying, complaining, etc.
Others may argue it isn’t necessary to do anything. I disagree. I believe it is essential to improve the quality of laboratory testing if we are to avoid another round of laboratory regulations (perhaps CLIA-2010). The case for improvement is supported by principles of Total Quality Management (TQM), particularly the emphasis on understanding customers’ requirements for quality in order to properly plan and manage production processes. The implication for laboratory testing is that we must know the analytical quality required for each of the tests we perform, select measurement procedures with the precision and accuracy necessary to satisfy that requirement, and implement QC procedures that will reject runs when the analytical errors that exceed the quality requirement.
Are we currently managing the analytical quality of our testing in this way? Do we know the quality we want to achieve? Do our QC procedures have the necessary sensitivity to detect critical-sized errors? If not, what is the meaning of quality control? Are we just doing arbitrary control, not quality control?
How do we put quality into quality control? The CLIA regulations and the FDA guidelines provide a good starting point for improving quality systems, but we may get bogged down in all the individual rules rather than developing the necessary quality system. The problem is that the quality system needed for one test may be different from that needed for another test. We must plan QC procedures based on the quality required for individual tests and the performance achieved by individual test methods. The solution to the problem is to develop a QC planning process that provides the appropriate QC system for each test.
Through proper planning of QC procedures, a laboratory can achieve a defined level of quality in daily operation and assure that test results satisfy customer requirements. Laboratories should do this as part of good quality management, regardless whether government regulations require it. Control procedures that are planned in this way actually build quality into the testing process, in contrast to current control practices where control rules are often set in an arbitrary way. It's time to move forward and manage quality in the proper way. That means putting quality into quality control to assure that laboratory tests meet stated levels of quality.