Sponsored Roundtable
August 2025—This is the second of a new feature in CAP TODAY: a one-on-one virtual roundtable in which CAP TODAY publisher Bob McGonnagle speaks with one vendor and one laboratory expert to spotlight a company and a customer for their laboratory solutions and work. ZeptoMetrix is the sponsor of the following roundtable, which took place May 14.
Jessica Van Allen, PhD, is technical support lead for ZeptoMetrix. Meghan Starolis, MS, PhD, HCLD(ABB), is senior science director for infectious diseases at Quest Diagnostics, Chantilly, Va.
Jessica Van Allen, I’d like to talk about some of the hot topics in molecular infectious disease testing, and you mentioned in our discussions offline that viral load testing for transplant viruses is becoming ever more important in the field. Can you make a few remarks about that?
Jessica Van Allen, PhD (ZeptoMetrix): There’s testing that is done using laboratory-developed tests and testing performed using FDA-cleared assays. Those are the two big buckets of testing in the labs of our customers. Meghan and I attended a conference recently at which a couple of the speakers talked about viral load testing for common transplant viruses—EBV, CMV, VZV, some adenoviruses. We’ve been playing in that field for a long time in terms of molecular controls for viruses, so they’re products we’ve had on the shelf. But we’re always looking to get feedback from end users and customers on how we can approach new products or adjust what we have on the shelf to support them in the testing they need to do in terms of levels, strains, concentrations, packaging.
Meghan, tell me about testing viral load for transplant-related viruses within the Quest laboratories.
Meghan Starolis, MS, PhD, HCLD(ABB) (Quest): Within Quest and with laboratories in general one issue related to transplant viruses is the commutability of test results. Often the transplant recipients have their transplantation procedures at a center of excellence or a transplant center that could be hours from where they live. After they’ve had their transplantation we need to monitor them for latent viruses that may reemerge once they’re on immunosuppressive drugs. Until recently, we’ve mainly had lab-developed tests for these types of viruses. And the lab could pick different calibrators, different stock material that could be quantified in various ways—TCID50, Droplet Digital PCR, copies per mL. And for a long time we didn’t have an international standard. But we know this is very important for transplant patients because as they leave the transplant center and return to their homes, they might be getting testing done in different labs. So having standard tests from the major vendors but also control material and calibrators that are calibrated in international standards will help us be able to compare viral loads over time, no matter what laboratory did that person’s testing.
Jessica, it’s going to be important that we have a well-characterized control. And you’ve mentioned to me that it’s important to have quantitative results for the various controls so that dilution and other studies can be done. Can you paint this part of the picture for us?
Dr. Van Allen (ZeptoMetrix): When you’re looking at things like viral load testing in particular, you’re looking for a specific quantity. And as Meghan said, to that point of commutability, you want something as close to a patient sample as possible when you’re talking about a control or a calibrator, so you know the results are accurate. It’s important that you have, one, a control on the plate that you trust, that you know is giving you a correct positive or correct negative, and, two, a calibrator on the same end that is giving you an accurate result. We’ll continue to hear about this as assays become more standardized and more FDA-cleared tests come on the market for these kinds of things. You’ll shorten that variability that can occur between labs, which is great. But from what I have gleaned from the talks I’ve heard in the past few years and recently, there’s definitely progress still to be made to that end with these specific assays.
Meghan, you have stressed in our previous conversations the importance of understanding what might be in a test kit, or what even might be in an LDT “formula” or recipe. Could you expound on that? When we talk to ZeptoMetrix we’re talking about a third-party control with the ability to do many different things, as we’ve just heard, particularly with quantitative dilutions and ranges and so on, but tell us more about the importance of understanding what a third-party control is and is not. And talk about what’s in the kit.
Dr. Starolis (Quest): As lab directors, when we are choosing QC for our assays, it’s important that we understand the difference between an external control as defined by our regulatory organizations and third-party controls. In my experience, having been a laboratory director, at times people use these terms interchangeably. For instance, if there’s an FDA-cleared kit that comes with a control, a laboratory may think it needs to add another control as an external control that’s a third-party control.
If you look at the CAP’s definition of an external control, it is simply a control that is external to the reaction, as opposed to an internal control, which is part of the reaction. The CAP guidelines provide examples of what can qualify as an external control, and they say it could be a kit control, a third-party control. It could be a previously run patient sample. It could be a control you create out of some kind of stock material.
As a lab director, when do you need to purchase a third-party control? I recommend analyzing the controls that come with the FDA-approved test kit. The instructions for use with the assays usually give a pretty good description of the control material. It will say “whole organism in this matrix,” or it may say “armored RNA in this matrix,” or it could say “nucleic acid.” We want our external controls to be full process controls—to control for the entirety of the process, including extraction, preprocessing steps, or an amplification at the end. If you have a kit control that is nucleic acid, that may not be a full process control if it doesn’t require extraction.
When I’m looking at any kit that comes with a control, I analyze what that control consists of, and if it is not a full process control, then I will select a third-party control, and I’m going to reach out to someone like Jessica and ask questions about that control. What is it made of? Is it a full process control? Does it control for what I think it’s controlling? Folks like her at these companies are amazing resources.
Jessica, can you talk about your end of that same question? It’s easy to think someone calls up the ZeptoMetrix 800 number and says they need a control for whatever it is. There’s a little more to it, isn’t there? The person on the other end of the phone perhaps has questions they’re too embarrassed to ask, but you’d encourage them to ask those questions, and you could give them a lot of help. Is that right?
Dr. Van Allen (ZeptoMetrix): Yes, it is. There’s no need for a phone call if they’re not comfortable with it. I run the tech support email, and many questions come in that way. I also interact with customers at meetings. But always I give my card and say, “Please ask first,” because there are so many instances in which someone buys something because they heard about it from someone and they think it’ll work for them. Sometimes it will—they’re fine and no harm, no foul.
But people don’t want to ask a dumb question, although there’s no such thing when you’re spending money and trying to find what will work for your laboratory and your processes. We try to put a lot of information on our website and in our product inserts, in the documentation that comes with our materials. But I always encourage people to reach out directly. Why take the risk of wasting money or time in trying to get something going in your lab when you don’t have to? That’s what we’re here for. And one of the benefits of working with a supplier of third-party external quality controls is that we can do the legwork for you. We know what is in our controls, what their capabilities are. So why not use that resource?
That’s an excellent point, and I hope we can underline it yet again. Meghan, I want to talk to you about a question I’m sure comes up in your laboratory because samples tend to arrive at the door and it’s left to you and your colleagues to figure out what the samples are and what the questions are that people have about the samples. So I will choose one here. Many different sample types arrive, some of which would be approved for FDA-approved kits, but there are many beyond those. Could you talk about the importance of understanding the specimen you’re looking at and the appropriate use of controls and testing based on the variety of specimens you see?
Dr. Starolis (Quest): First, we do need to make sure any specimen type we accept is validated if it’s not part of the FDA-approved kit. If the kit is FDA cleared for plasma, for example, but we want to accept whole blood, the laboratory needs to do a validation of that sample type, before we accept it, to ensure it works properly and yields expected results. But assuming the lab has done that and has its validation in place, it’s important to think about any controls you may need to add to your assay if the sample type you’ve chosen requires any preprocessing.
HPV testing is an example. If you’re using an assay that’s validated for ThinPrep but you want to be able to accept SurePath, in many cases there’s a preprocessing step that’s needed for SurePath. It could be like a proteinase K digestion that’s different from what the lab has done with the FDA-cleared samples. So, again, going back to that CAP requirement, the controls need to be full process controls. If you have validated a sample type that requires some other type of preprocessing, you need to choose an external control that goes through the same process.
Additionally, if you have validated a sample type that is particularly hard to extract—whole blood, for example, but actually our extractors are quite good at extracting whole blood these days—then you may want to consider adding a control to that matrix to ensure you have adequate extraction of your sample.
Jessica, a laboratory might call you and say, “We have an exotic specimen and it’s the only one we have” and ask, “Do you have protocols you could share with our lab to help us adequately run this specimen using ZeptoMetrix controls?” Correct?
Dr. Van Allen (ZeptoMetrix): Yes, if we have the organism in-house and we sell it commercially, I’m always happy to share what we do internally—the processes and the extraction kits and the instruments we test on—with the understanding that it might not be exactly what you do, but here’s how we see it and how it is handled in our hands. That is typically enough to get them started. As someone who’s worked in technical support for several years now, I do have a lot of feedback that I track and can go back to and share with others. And as I said, I’ll always share our internal information, whatever I can to help troubleshoot.
Along that same line, someone might naively think that with a company like ZeptoMetrix, you just have a basic dinner menu: Here are the controls we have for these kinds of tests or organisms. But there’s a lot more to what you have on offer.
Dr. Van Allen (ZeptoMetrix): Yes, there is. Like I said, we try to have as much information as possible on our website, but we do have a number of agnostic controls that should work across platforms and assays. We have controls with known performance on specific FDA-cleared assays. We have many live organisms and heat-inactivated culture fluids and DNAs. If it’s not on our website, it might be an organism we received a couple of weeks earlier for a custom growth of something; it might turn out to be useful and it’s emerging and we might want to turn it into a product. Again, it is worth asking, If we don’t have it, can we source it? Or do you have a source for it and we can get it in and work with it in our workflow and turn it into something usable for you? Those options are all on the table for us.
Meghan, you have at Quest as many as 26 laboratories you need to service for infectious disease.
Dr. Starolis (Quest): Yes, laboratories that perform molecular tests. A handful of our labs are referred to as our esoteric labs where we do our highly complex laboratory-developed tests. But with FDA-cleared tests, we’re doing that—depending on the test—at up to 26 sites.
In many cases, you need to have controls with organisms present at a very high titer so you can do dilution studies. Correct?
Dr. Starolis (Quest): Yes, it is correct. We like high-titer stocks when we’re doing both validations of LDTs and verifications of FDA-approved tests. The types of studies that have to be done are different, but in all cases we want to be able to have high-titer stocks on which we can do dilutions to test the linear range—in our accuracy studies we’re supposed to have high, medium, and low samples—so for our low samples we can get that quantitative value close to the sensitivity limits of the assay. We can control that more closely if we have a material that can be diluted from a high titer. So we use these types of things for nearly every type of validation or verification study we do. And what I like to do at Quest is work with a company to have a standard lot that has a known quantitation for all my various sites so I can help oversee those validations or verifications at the laboratories I support.
Jessica, you can provide some of those high titers, but sometimes you’re doing it with live organisms, sometimes attenuated organisms. Tell us more about this element and the biosafety elements of these important controls.
Dr. Van Allen (ZeptoMetrix): Often when people think of us they think of our ready-to-use QC material that’s inactivated, kind of diluted already in the matrix, ready to go on an instrument. But to Meghan’s point, we also have a catalog of quantitative high-concentration material like she’s talking about, where you can dilute it into your matrix of preference at the level you require for the work you’re doing. When we don’t have it chemically inactivated in our natural format, we might have it as a live titered material or a heat-inactivated culture fluid. It’ll be in something like a CFU per mL value with a bacteria, and with a virus typically a TCID50 per mL if it’s a titerable virus, whereas with our natural inactivated products that we’re testing by PCR, you’ll get a copies per mL or IU per mL value where possible.
We are always talking about a medical and scientific result, which is enormously important. At the same time, though, we’re all operating with income and expenses. So let’s talk about the cost of quality. One way to put it is: What is the cost of poor quality? Do you sometimes see people who have been trying to cut corners and then realize they need to go back to better practices, even if they’re somewhat more expensive?
Dr. Van Allen (ZeptoMetrix): Yes, we do see that, and it’s common. Typically it is someone having to decrease the window, the time frame in which they’re doing their testing. They’re not doing frequent QC. They’re doing monthly or every other month or—and we hope not—every six months and using a proficiency program as their only QC. The risk goes up depending on how many patient samples are being run and how many results are given back. If you’re a small lab, it’s probably not that large a risk. But if you’re a lab that’s seeing dozens or hundreds of patient samples a day, you have to consider the downstream impact of a false-positive or a false-negative result, not only for the patient but also for the laboratory itself.
Meghan, Quest’s volumes around the country are staggering, so the responsibility too is equally staggering. Talk about this cost of quality and what you’re doing using controls to provide the highest possible quality at the best possible cost.
Dr. Starolis (Quest): The cost of poor quality is something we talk about frequently at Quest. Saving pennies and having a major issue can cause big downstream repercussions. You can lose clients. You can lose the trust of your physicians. Depending on the organism, you can have litigation. The cost of poor quality can be staggering.
So what I like to do and what I encourage others to do is to treat each assay individually, and when it comes to controls, don’t be on autopilot. Take time to really read your IFUs if you’re using an FDA-approved test. When you’re doing LDTs and FDA-cleared assays, take time to do a risk assessment. If it’s an open system test, it’s more prone to contamination versus a closed system test. Think about your specific test. What are the risks? What are the repercussions clinically of a false-negative and a false-positive? And then think about whether you need extra controls to control for these outcomes.
I encourage reaching out to someone like Jessica because the control you’re choosing may not be controlling for the outcome you’re trying to prevent if you do not have an awareness of what’s in that control. Someone like Jessica can advise you: “You’re worried about false-positives—this would be a good control to use.” Or: “You’re perhaps worried about a false-negative because of genotype diversity of the organism—maybe try this approach.”
We are keeping cost in mind. We’re not overengineering our QC, but we’re doing the right amount for impeccable quality.
Jessica, a couple of questions for you from the audience. One is what frequency you would recommend for testing using third-party controls in addition to manufacturer controls.
Dr. Van Allen (ZeptoMetrix): The answer is the point Meghan made: Each laboratory has to take a look at it and do a risk assessment. If you’re looking at an FDA-cleared test, you’ll want to refer to the manufacturer’s IFU, to see if there is guidance. But it does come down to doing a risk assessment in your laboratory and understanding what a natural or useful cadence is for your laboratory and that particular assay.
Does ZeptoMetrix have a solution for HIV-positive samples to run in a correlation study?
Dr. Van Allen (ZeptoMetrix): Yes, we have HIV-positive material, so please reach out so I can direct you to the right solution.