Questions & Answers from the live event
Is a control different than a calibrator?
Yes, typically calibrators are solutions with a defined, specific concentration that are used to set or calibrate an instrument or system before testing is started. Most times, they are provided by an assay or instrument manufacturer. The purpose of a control is to validate the reliability of the test system and evaluate outside factors such as operator performance and environmental conditions that could influence results. Like we talked about in the presentation, controls should mimic patient samples to challenge the full process of the assay in question.
How often should controls be run?
In many instances, there is no clear guidance on how often controls should be run. You should follow the Internal Quality Control Program (IQCP) as established in your laboratory. IQCP permits the laboratory to customize its QC plan according to test method and use, environment and personnel competency while providing for equivalent quality testing. You can also reference the manufacturer’s instructions for the assay or platform you are using. It may offer guidance specific to the instrument/test.
How do I know what kind of controls I need for my lab? That is, qualitative vs quantitated, panel vs controls.
The kind of controls you need obviously depends on the tests that you are running in your lab. The technical experts at ZeptoMetrix would be happy to work with you in determining which products that we offer will align with your laboratory’s quality control plan.
Is the term quantitated the same as the term quantitative?
Yes, those terms are used interchangeably.
ISO said we should try to consider using a QC close to our test sample matrix. We analyze urine with a microarray but cannot find any external QC or proficiency supplier to do this. Any recommendations what we can do, as we are wanting to get UKAS accredited?
We are not aware of any control suppliers who use urine as a matrix. At ZeptoMetrix, our matrix is intended to be a mimic for clinical specimens in general and is not restricted to one type necessarily. We use this diluent in a variety of panels and controls that work with various assays and platforms with different sample types. How do you establish 'expiration' or storage requirements for QC material? For our controls specifically, real-time and/or retrospective stability testing has been performed to verify the expiration dating of our materials at the recommended storage temperature.
Why is antigen test % worldwide higher than US? Does it indicate difference in approach?
It’s possible that it indicates a difference in approach. It likely comes down to a variety of things: cost, ease of use, ease of manufacture, turnaround time, availability of tests already on the market, etc. It will be interesting to see the trend play out over the next year or so as routine testing will likely continue to ramp up.
Which factors are not monitored by internal controls?
That’s very specific to both the kind of internal control being used and the actual test/assay that it is being used for. Internal controls or built-in controls for some kits, for example, may only do so much as to indicate that all the reagents included in the device are active and working properly, while built-in controls for another kit may simply indicate that a sample was added, and the test device ran correctly. The manufacturer’s instructions should detail what their specific internal controls monitor thus helping you determine whether additional controls may be needed. Many laboratories incorporate unbiased, third-party controls as part of their IQCP protocol to provide a full-process control option that monitors the integrity of the entire test system.
Many labs use patient-known samples as external controls. Is this OK? What challenges might they face?
You’d have to check with specific federal or local guidelines as well as any specific accreditation bodies to determine if patient samples are an acceptable source for external controls. While they certainly would function as full-process controls, it may be more time-consuming and costly to maintain cultures and stocks of these materials in the long run. There should also be some method to periodically check for purity as well as monitor performance over time to ensure stability and material consistency.
