Virtual Town Hall 8-4-21 

Moderator: Elias Mallis 

August 11, 2021 

12:15 PM ET 

Elias Mallis: Greetings, everyone, and thanks for joining us today. I'm Elias Mallis, director of 

the Division of Industry and Consumer Education in CDRH's Office of Communication and 

Education. I'll be your moderator for today's program. Welcome to the CDRH Virtual Town Hall 

Meeting for developers of tests for SARS-CoV-2. This is meeting number 66 in our series during 

which we'll discuss and answer your questions about tests in the fight against COVID. 

Our panelists for today's program are Dr. Timothy Stenzel, director of the Office of In Vitro 

Diagnostics and Radiological Health, or OIR, in CDRH's Office of Product Evaluation and 

Quality, and Toby Lowe, associate director also from OIR We'll start today's program with some 

opening remarks and updates from our panelists, and then we'll spend the rest of our time today 

answering your questions about the development and validation of COVID tests. 

Please note, we're not able to discuss specific submissions that are under review. To ask a 

question, please go to your name on the Zoom meeting and select the Raise Your Hand icon. 

Now let's turn the program over to Tim for some opening remarks and updates. Thank you, Tim. 

Tim Stenzel: And thank you, Elias, and welcome again. 66, wow, that number keeps coming up 

and will continue to. And we already have a number of attendees, and thank you for joining us 

again. Again, our purpose here is to assist you in order to assist the nation's response to the 

ongoing pandemic. 

And obviously, testing needs to persist with the Delta surge in the US that continues to go up. 

The amount of testing is going up, and obviously, the positivity rate is pretty high compared to 

earlier this summer and is hovering nationally around 10% right now. And there are certain areas 

where it's-- currently numerous areas where it's much higher than that even. 

I just wanted to again go over some key current priorities. As I mentioned, the importance for 

testing is ongoing, and the demand's ongoing. And so it's very important. And our key focus is to 

do anything we can to significantly expand access to testing through a high-volume test to 

support high-volume testing. And so that is the best use of our public resources, public health 
 

resources, is to focus our attention on that. And we're trying to stimulate development of those 

kinds of tests. 

So tests, particularly I would say diagnostic tests, in high-volume central lab tests systems that 

can run through a ton of samples in a shift, and they're manufactured in high volume. And then 

point of care and home tests, so diagnostic tests that, by virtue of their higher distribution, being 

performed in a lot more sites than, say, a high complexity lab, tens of thousands of CLIA waived 

labs and hundreds of thousands actually of CLIA waived labs and obviously potentially tens or 

hundreds of millions of home sites. 

And so to supply those over 100,000 point of care labs and as many households there are in the 

United States, that does require a high manufacturing volume of point-of-care tests and in-home 

tests. So for those that want to know if they qualify and meet the high volume considerations, 

they can reach out to the FDA and ask if their technology will meet that. 

I also wanted to briefly cover the bar that the EUA provision allows her to use to make decisions 

on authorization decisions on tests, and these are primarily focused at SARS tests and diagnostic 

tests, and that bar is that the likely benefits outweigh the likely risks. 

As we move through the pandemic and as the virus mutates and new variants show up and others 

recede, this balance between likely benefit versus likely risk can alter. And so that is a fluid sort 

of bar that we apply going forward. It hasn't changed drastically, but it does enter into our 

thinking. It is the standard that we use for making authorization decisions. 

And of course, the target is SARS. That's what the EUA provisions are for. They aren't for other 

viruses, but we have-- obviously, the FDA has shown a good deal of flexibility to allow other 

viruses and panels to be submitted to the FDA. And those panels when produced in high volume 

are able to be tested in labs in high volume do remain a priority. All right, enough on priorities. 

We've covered all that before. 

Also, we have recently obviously switched to a new platform, the Zoom platform, and there are 

clear advantages to it. But in moving over to this platform, we have had a challenge of dealing 

with transcript generation. And the awesome team that we have here at the FDA has been 

working on that, and we are working as hard and quickly as we can to restore the previous 

timelines for posting transcripts after calls. 

And we do see a light at the end of the tunnel and hopefully in the relatively near future. So in 

the interim, we do ask for your patience until we get back to those previous timelines for 

transcript posting. With that, we can move into the phase of the call that we usually go to, which 
 

is we address the previously submitted questions, and for that, Toby, I will turn it over to you. 

Thank you. 

Toby Lowe: Thanks Tim. Thanks, everyone, for joining us again this week. The first question 

that we received actually goes nicely with Tim's talk about priorities. The first question is about 

an EUA for a multiplexed molecular assay that includes Flu A, Flu B, and COVID and 

specifically asking if it's possible to request an EUA for over-the-counter use of a multiplexed 

molecular assay. 

And as Tim indicated, we do prioritize multiplex, multi-analyte panels when they're sufficiently 

high volume, but we have not currently authorized any tests either under EUA or traditional 

marketing pathways for over-the-counter flu tests. And that's because there's just generally not a 

need to screen asymptomatic individuals for influenza. 

So Tim was talking about the benefit-risk calculations that we take a look at, that impacts the 

benefit-risk calculation. So for flu tests, we have not determined that there is a benefit to overthe-counter flu tests. So that means that while we are considering multi-analyte panels for EUA, 

we are not currently doing so for over-the-counter. 

We are reviewing and authorizing over-the-counter tests for SARS-CoV-2 under EUA because 

there is a need for asymptomatic screening for COVID-19. But for multi-analyte tests, we are 

generally just considering prescription use tests since they're only needed for symptomatic 

individuals or those otherwise suspected of infection. 

The next question that we have is regarding a point of care clinical evaluation and conducting--

so the clinical evaluation at a CLIA waived site with testing patient specimens, and then there's a 

portion of the template that also talks about testing with samples prepared with SARS-CoV-2 

near the LOD of your assay in clinical matrix. 

And the question is asking for the contrived sample testing discussed in the template, do all of 

the clinical sites have to participate, and do all of the operators in each site have to participate? If 

they're having difficulties with that, can they find other sites which do not participate in the 

initial clinical study to do the contrived sample testing? 

So an efficient way to execute that study would be to incorporate the contrived testing into the 

workflow of the clinical test sites that are performing the clinical validation study. But using 
 

 

clinical sites that were not part of the clinical validation study is also acceptable if they meet the 

recommendations noted in that section of the template. 

Specifically, we don't require that they be tested at the same site, and they can all be tested at one 

site, but we do expect the operators to be actual point of care operators and not employees of the 

sponsors or the clinical investigators. And we do typically request the educational backgrounds 

and professions of the operators to ensure that they're representative of the intended user. 

The next question that we have is about clinical evaluation of an over-the-counter home-use 

antigen assay that can be interpreted either visually using paper instructions or using a 

smartphone app on either iOS or Android-based smartphones asking about the target distribution 

of enrolled participants who use the paper instructions versus the app and asking whether a 

certain number of the 30 positives have to come from participants using paper versus the app. 

So generally, for a situation like that, we would expect to see 30 positives and 30 negatives for 

visual interpretation and another 30 positive and 30 negative for the app interpretation since 

those two methods may lead to significantly different performance. And we would also expect to 

see usability for both approaches. 

The next question we have is also for home-use rapid antigen testing. The question is regarding 

the template indicating that home tests should either have an internal control to verify that 

adequate sample is collected or mitigate the risk of sample collection error by having another 

feature like a video observation, and they're asking if that recommendation is still in effect. And 

yes, that recommendation is still FDA's current recommendation. 

We consider each test individually and consider the mitigations that are included to enhance the 

robustness of the test when we do our benefit-risk evaluation. We do continue to recommend an 

internal control or other medication to ensure that adequate human sample is collected. And at a 

minimum, we recommend that there be an internal procedural control to ensure that the sample 

adequately flows up the test strips for lateral flow test. 

The next question we have is regarding the use of contrived samples in a clinical trial for homeuse test. This one is specifically asking about a home-use over-the-counter multi-analyte 

molecular diagnostic test. So as we discussed for one of the previous questions, we are not 
 

generally considering over the counter for multi-analyte tests since there is no need to test 

asymptomatic individuals for flu at this time. 

However, we can address the other questions that came in this inquiry which are generally about 

the use of a combination of prospectively collected positive fresh samples and positive contrived 

samples in a clinical study or the use of banked or archived samples. And at this point, the rate of 

new confirmed cases in the US is very high unfortunately so patient samples are readily 

available, and we do recommend acquiring and testing patient samples during the clinical 

evaluation validation studies. 

Our current recommendations for multi-analyte tests, which again, would not be over the 

counter, can be found in the molecular template, and for multi-analyte tests where the nonSARS-CoV-2 analytes are not previously cleared, we recommend providing data from testing 

positive patient samples from at least 50 positive patient samples to validate an RSV detection 

claim as part of a SARS-CoV-2 multi-analyte test. And you can take a look at the instructions for 

use that we've posted on our website for more information on the validation that we've been 

looking at for molecular tests, which include RSV. 

And banked sample can be used for point of care moderate and high complexity molecular tests 

but not for home tests. And antigen point of care and moderate high complexity molecular tests 

can use banked samples with point of care testing a minimum of five fresh positive samples for a 

fresh sample claim and authorization with a post-market commitment to complete the fresh 

study. 

Tim Stenzel: Yeah, just to clarify, the antigen point of care [INAUDIBLE]. But if they can use 

banked samples and frozen samples, we would like to see a clean set of fresh negative samples 

and a minimum of five fresh positive samples. But again, almost half the samples for home test, 

whether they may be molecular, antigen, we do need to see fresh samples for home 

authorizations. Thanks, Tony. 

Toby Lowe: Thanks for adding that clarification, Tim. The next question we have is regarding a 

clinical study to support a five ten case submission of a SARS-CoV-2 multi-analyte PCR 

molecular assay using the BioFire RP 2.1 as a reference method. And they're saying that their 

current understanding is that a minimum of 50% of the prospectively collected specimens need 

to be tested fresh with the candidate test and asking whether they also need to be tested fresh 

with the reference method, or can samples be tested frozen provided that testing aligns with 

specimen stability in the package insert. 
 

 

 

We do recommend that testing the comparator method using fresh samples, but testing using 

previously frozen samples is likely acceptable for molecular tests if an appropriate freeze-thaw 

study is available. The comparator method testing frozen samples is a risk since samples can 

degrade over time or if improperly stored. 

Next question we have is--

Tim Stenzel: I didn't unmute fast enough. I just want to make clear that we do want to see a 

prospective fresh study. It's only if you're unsuccessful in getting samples that we'll be open to 

using particularly banked, banked deposit samples, too. And we want you to have a dialogue 

with our review team at that point just to make sure everything is going to be good. But we do 

understand that hopefully flu and other respiratory virus will stay low for a very long time. That 

would be awesome. But that does present challenges for full authorization of tests, and we want 

to be flexible as possible. Thanks. 

Toby Lowe: Thanks for adding that, Tim. The next question that we have is another question 

about an over-the-counter COVID plus influenza A/B test. So again, we'll reiterate that we 

generally do not think that the benefits of an over-the-counter multi-analyte test outweigh the 

risks. So we would limit the multi-analyte tests to prescription use since health care professional 

involvement is generally needed to ensure that test results are interpreted correctly and that 

appropriate action is taken. 

The rest of this question is asking about the recommendations to include 20% to 25% of samples 

with low viral load plus or minus 3Ct of the LOD of the comparator device and expressing some 

confusion about how to define those low viral load samples. So to clarify that, the low positive 

samples return a CT value within plus or minus 3 CT of the LOD CT of the comparator test. The 

LOD of the candidate test does not impact the evaluation of a low positive sample tested as part 

of a clinical validation. So again, it is low positive as tested by the comparator test. 

And then the last question that we have here is asking about FDA review priorities for COVID19 IVD sponsors who would like to submit a de novo or 510(K) instead of an EUA and asking if 

the FDA is encouraging non-EUA submissions for COVID-19 IVDs. But for tests that will most 

benefit the current public health needs, EUA remains the fastest and least burdensome route to 

authorization, especially considering the level of evidence that we're asking for for an EUA 

versus a full marketing authorization. But sponsors that are interested in pursuing full marketing 
 

 

 

 

authorization through de novo or a 510(K) are also welcome to do so. And Tim, unless you have 

other things to add there, we can go to the live questions. 

Tim Stenzel: Let's go to live questions. Thanks. 

Elias Mallis: All right, thanks, Tim. Thanks, Toby. So again, if you have a question for our 

panelists today, please click the Raise Your Hand icon, and we'll get you on the list. So let's start 

off with our first question from Richard Montagna. Please unmute yourself and ask the question. 

Richard Montagna: OK, thank you. We just finished preparing a presub for a multiplex PCR 

test for an expanded respiratory panel that will detect SARS-CoV-2, Flu A and B, RSV A and B, 

and we were uncertain as to how to actually submit it because since it's a SARS-CoV-2 related 

product, we weren't sure if we should just email it in through the OIR operations email or send it 

in formally through Document Control Center. So--

Tim Stenzel: This is for a full submission, correct, not an EUA? 

Richard Montagna: Correct, yeah. It's to describe--

Tim Stenzel: I would use the traditional pathway for that. Toby, anything else to add? 

Toby Lowe: Yeah, absolutely. If you're submitting it as a formal P-sub as opposed to a preEUA, we would ask that you use the normal processes for submission. 

Richard Montagna: OK, so we'll send an electronic copy in through the Document Control 

Center. 

Perfect. Thank you. 

OK, thank you very much. 

Tim Stenzel: And I would also add, I mean, we are starting to get an increasing volume of Qsubs, Presubs for full authorizations. When it's a molecular test, we've already made one 

decision, and so it would be hopefully the decision summary has been posted already. I don't 

know. But we do have recommendations. So by and large, we hope that you get everything you 

need from that. 
 

 

 

 

And so because of the growing volume of Q-subs, Presubs, we are going to aim to probably be 

fairly succinct in our responses and focus on anything that might be unique. And we ask your 

patience with this because of the high volume. We're still getting more than 100 EUA 

applications a month, and obviously, we're still working on all our non-COVID work as well. 

And then, we're going to endeavor to update the templates for molecular serology and antigen 

tests to make it very clear what the recommendations are for conversion and upcharge the team 

to make that a high priority now to make that available. I can't promise when. But then, it should 

minimize the need for Presubs and Q-subs and minimize any timelines for getting feedback from 

the FDA. 

But in essence, we by and large, especially for molecular, have recommendations. We can 

provide our general recommendations pretty quickly. And then only if there are unique specific 

questions that we're focusing on working on. So I just want to let everybody know who is 

thinking about this and looking at this. So thank you for the opportunity to share. 

Richard Montagna: Good. Thanks, Tim. 

Elias Mallis: Richard, thank you for your question. Let's go to our next caller, Melissa 

[INAUDIBLE]. I hope I didn't mispronounce your name. Please go ahead and start your 

question. 

Tim Stenzel: I think Melissa is muted. Yeah, now we can hear you. You were muted before. 

Melissa Fertiguide: OK, OK. Thank you. Thank you very much. And here is the question is that 

there are a lot of COVID-19 variants. Which ones do we need to do verification by applying for 

EUA, and what specific verification do we need to do? 

Tim Stenzel: What kind of test are you developing, molecular? 

Melissa Fertiguide: Oh, no, just a OTC COVID testing. 

Tim Stenzel: For molecular antigen? 

Melissa Fertiguide: The antigen. 
 

Tim Stenzel: Antigen test, OK. Well, when you do your clinical studies, if they're happening 

concurrently with your development and just prior to your submission, you're going to be testing 

the current circulating variant, and we don't necessarily ask you to identify which variant. 

But if the test performs well with the current contemporaneous variant that are circulating during 

the time of the clinical study, that gives us an idea at least for what's currently circulating the 

performance if it was adequate or not. But we do also want you to do an assessment of 

sequenced variants and mutations and the potential impact of those on your test. And you can use 

bioinformatics to help you. 

For an antigen test, knowing the epitope mapping for your antibodies and/or knowing the antigen 

that was used to raise your antibodies can give you a clue as to whether or not you should do any 

subsequent at least in silico investigation of potential impacts. And for any potential impacts that 

you identify or the FDA identifies, we may recommend some wet testing of those variants to 

make sure that you don't have a performance issue. 

And that wet testing could be if the specific invariant or variants of concern are present in, say, 

BEI Repository and have an activated virus and that functions in your assay, that's one potential 

pathway. Another potential pathway is to obtain residual samples that have been sequenced so 

we know what the mutations and variants are. And there are some labs out there that are 

routinely doing sequencing and have banked samples or can sequence the samples for you. And 

that should help you determine whether or not there is a real issue with your antigen test. 

But this is a high priority to determine the potential impact of variants of mutations on all tests, 

EUA tests. It's an ongoing activity at the FDA, the CDC, and of course, NIH and RADx, and 

we've been working really closely together along with the developers of tests to assess impact. 

So hopefully, that more than addresses your question. 

Melissa Fertiguide: Oh, thank you very much, sir. And also, the CDC has recommended the 

labs to perform the testing for the variant? 

Tim Stenzel: I would look at the labs that are doing the sequencing routinely and approach them. 

I don't think that we maintain an approved, authorized, or suggested list. 
 

 

 

Melissa Fertiguide: OK. 

Tim Stenzel: But again, that's only going to be recommended if there's a potential impact of your 

test following your analysis of potential impacts and our analysis during our review of your test 

for any potential impact. 

Melissa Fertiguide: OK, I see. So as we already submitted the pre-EUA application, so and later 

about two months for that review, after we get the first response from the review, we will see that 

if the FDA will request any additional testing. 

Tim Stenzel: Yeah, I don't think so unless they're at least providing information of potential 

impact. If you know of potential impact, I would just go ahead and do that. And for those that are 

waiting, this is a test, an antigen OTC test where we have authorized, I think, six authorizations 

for OTC antigen tests already. And we're going to authorize more. So I'm not sure what you're 

asking in a pre-EUA that you need to wait on our feedback. 

As I stated earlier, we are still seeing high volumes of pre-EUAs and original EUAs as well as 

amendments and supplements. So we're remaining extremely busy, and you really-- if you're 

following what others have done before and our decision summaries for those, I mean, it's really 

low risk. If you're listening on these calls and you're just doing the standard things, I would urge 

you to move forward in your development program on risk. We'll get back to you as soon as 

possible. 

And if we can sort of move to a place where we're really only asking in pre-EUAs and in Presubs 

for SARS tests that we're only asking the unique questions up front. That would really help all of 

us to focus on just the most important questions here. All right, we do need to move on. We do 

have a long list of callers. Thank you. 

Melissa Fertiguide: Thank you. 

Elias Mallis: Thank you, Tim. Yes, we have a number of hands raised so let's get to these 

questions. Arvita Tripati, you are next to ask your question for our panel. 

Arvita Tripati: Hi there. Are you able to hear me? 
 

 

 

 

Elias Mallis: Loud and clear. 

Arvita Tripati: All right, excellent. So my question is for non-lab test kits, how is the FDA 

differentiating between low volume and high volume with regards to the quantity of tests 

allowed in a given kit? 

Tim Stenzel: Well, again, this is home tests? 

Arvita Tripati: Yes. 

Tim Stenzel: Yeah, for home tests, if it's authorized for a single test in a kit, there are various 

options there and pathways depending on performance and what studies you've done where a 

single rapid antigen test in a home kit is sufficient. However, where the authorization comes with 

a serial testing claim say for screening, then we want to see at least two tests in a kit. 

So the high volume for that situation, same goes for point of care, isn't the kit size or the 

throughput of the particular test because these are more manual point of care and rapid antigen 

tests at home. And a given individual can only perform so many of these tests in an hour, and it's 

pretty low volume. 

So what we do when we look at that is we look at your manufacturing capability and how many 

of these tests can you produce, manufacture for US distribution in a given amount of time. And 

those thresholds, we haven't publicly announced. We may, but right now, we're not because we 

want to remain responsive to the current situations, and that can change. So we don't want to set 

a bar publicly necessarily, and then have to go and change it more formally later. So it gives 

maximum flexibility. 

And obviously, I think we've now authorized 27 antigen tests, I think, is the latest number, and 

that includes both home and point of care largely. There's maybe a few that are higher 

complexity, but those providers are producing tests in relatively high manufacturing volumes, 

and that's what we look at for our priority reviews. So if you want to know if you meet the level 

for review of priority, then you can reach out to the FDA and let us know that information, and 

we can let you know. OK? 
 

 

 

Arvita Tripati: OK, got it. What I was trying to clarify was around the size of the kit at which 

you would need a control. For example, we are going for a home use pathway, and so I've seen 

examples where there's one, two, I think up to six allowed in a pack for home use. At what point 

would we need to add in the control swabs? Would that be if we're making a Costco-sized pack 

that's 25 kits? Or is that a 100-kit pack? That's the high volume or low volume that I was trying 

to differentiate. 

Tim Stenzel: Yeah, we set the minimum number for recommended kit size based on the use. So 

again, if it's a single-use application, it only needs one test. If it's serial testing for antigen test, it 

needs two. And as far as external controls go in the home environment, we are not 

recommending that you actually have that. 

I mean, if your test requires for continued good performance to have external controls run, there 

could be some devices that require periodic calibration and/or check up calibration, that's more 

challenging in the home environment. And so it's ideal if you don't need those external controls. 

And of course, for waived labs point of care, there are monthly quality control requirements, and 

for those professional use tests, we do like to see that controls are available for the professional 

use so the folks in those environments don't have to go try to find a source for control to meet 

their CLIA requirements. So there's no cut off for number of tests that then requires external 

controls. It all depends on the technology and the location where the test is performed. 

Arvita Tripati: Got it. Thank you so much. That was really helpful. 

Tim Stenzel: OK, all right, we'll move on to the next caller. Thank you. 

Elias Mallis: All right, our next caller is from Greg S. Please go ahead with your question. Hey, 

Greg? 

Tim Stenzel: Well, Greg dropped something. Oh, he's on camera. But his hand's no longer 

raised. I don't know what happened. 

Greg S: OK, here I am. You there? 

Tim Stenzel: There you are, yeah. 
 

 

 

Greg S: Sorry about that. Tim, I know that you said the agency is monitoring commercially 

available COVID-19 tests to see if they're impacted by the Delta variant. I guess it's just a very 

general question, and maybe this requires specifics. But when you look at the dozens of 

commercially available COVID tests, can they detect the Delta variant? And can you parse that a 

little bit? Can test pick up on Delta but not necessarily say it's delta, and then does that matter, I 

guess, is the bottom line? 

Tim Stenzel: Yeah, so let me just go through our process that we use. So first of all, through 

safety communications, we have asked developers to engage in this along with us, and we don't 

want it to fall entirely to the FDA or the US government, but the US government has stepped up, 

and because we've been asked by the US government to make sure, ensure that the EUA 

authorized tests are still performing in the face of mutations and variants. 

And so on a weekly basis, we download the most recent sequences. We have all the proprietary 

primers and probes and other details about other types of tests like antigen tests, and we do our 

own bioinformatics search across all the tests and identify potential issues. 

We have a scale for determining whether it reaches the level in which we want to investigate 

further. And then if we do, we engage CDC and NIH RADx. And they try to source samples, and 

they try to obtain the tests to perform the actual test, particularly for antigen tests in NIH RADx 

labs. 

In addition, we do reach out to sponsors at that point, developers to do their own and for us to 

ask questions and for them to get back to us. And we do ask them to get back to us in a very 

timely way. And as soon as we have any sort of confirmed findings, we've been erring on the 

side of caution and posting results on the FDA website. 

But we do maintain a variant mutation website. Currently, there's only four tests listed there, and 

actually, none of those four have demonstrated a loss of sensitivity of 5% or greater, which we're 

currently defining as a significant decrease, for any of the variants of concern and for any 

mutation in the US or combination of mutation that reach the 5% or above level. 

So that's the good news, but we do have ongoing active investigations of potential issues. 

Fortunately, none are active for any of the tests that we would consider super high volume tests, 

and these are the super high volume rapid antigen tests, and we could come up with the list easily 
 

 

 

 

of the handful that are in that category, and you read about them the time, and also for the central 

lab test. 

So we do subdivide by whether it's lower volume, relatively lower volumes, moderate volumes, 

and high volume. Some of that is market penetration, too, as we're looking at how we grade the 

potential risk for the US testing activities, not that we don't investigate lower risk, but we want to 

be able to provide that kind of dashboard on a weekly basis to all our partner federal agencies. 

So the good news is for Delta nor for any other mutation or variant do we have any significant 

concerns at this moment. We do know that sequence information is not as numerous as 

sometimes we would like as far as new sequences on a weekly basis. And obviously, for some 

mutations that may not be a variant of concern, we don't always know at what point they reach. 

So we do continue to urge and recommend that for anyone performing testing, if they get a result 

particularly for a diagnostic test that doesn't match their clinical perceptions of what might be 

going on, that they reflex to another test, particularly a different test and particularly a different 

molecular test if the original test is molecular to confirm whether or not that original test result is 

accurate because any given test could, depending on whether it's three targets, two targets, or one 

target test, could have an issue, particularly the lower target test could have an issue with what I 

call a private mutation that isn't reaching significant levels, but obviously, it's critical for 

understanding what's going on with that patient. 

Greg S: Can I ask a quick follow-up? I mean, would you say generally that PCR tests are more 

accurate and sensitive to genetic variations of the coronavirus say compared to antigen tests? 

Tim Stenzel: Right now, all the EUA authorized tests are performing as expected that contain 

their EUA authorization or continue having EUA authorization. We don't have any information. 

Otherwise, we would not make that available or move to have them removed from the market. 

And as we've said before, and then we need to move on to the next caller, is that multiple target 

assays have a tendency to be more reliable than single target assays, and that's in our prior 

mutation coverage, and that makes good sense. So let's go ahead and move on to the next caller, 

please. 

Elias Mallis: Thanks, Tim, and thanks, Greg, for joining us on camera. Our next question comes 

from Wenli Zhou. 
 

 

 

 

 

 

 

 

 

Wenli Zhou: Hello, thank you for taking my call. So I have a question just to follow up with the 

previous conversation about the variants. So a couple of developers approach us because we are 

a CLIA lab and we do have a capacity to do some samplings or to do that to determine the 

variants, especially Delta variant right now. And the developer, antigen developer approach us 

and want us to determine if the sample specimen they're testing are Delta variants or not because 

they want to confirm their test can detect the Delta variant. 

So the question that they ask is, is your test and variant test EUA authorized? As far as I know, 

there's no such of EUA authorized variant test. So I guess my--

Tim Stenzel: We have a couple of whole genome tests, sequencing tests. They can report out the 

genotype. It's not part of the EUA authorization so that certainly aid. Can you focus on your 

question because we do have a number of folks, and I want to try to get through them? 

Wenli Zhou: My question is can we still do it? Can we still provide the test to them so they will 

use that for their submission or for their whatever their antigen development? 

Tim Stenzel: Here is the thing. If you're assisting their submission and you want to help them 

provide sequenced results, well, that's fine. We'll want to know some details about how you did 

your sequencing, though. 

Wenli Zhou: OK, so that have to be [INAUDIBLE]. OK, thank you. 

Tim Stenzel: And let's move on to the next caller. 

Wenli Zhou: Thank you. 

Elias Mallis: All right, our next call comes from Ivory Chang. 

Ivory Chang: Hello, this is Ivory Chang. Can you hear me? 

Elias Mallis: All good. 

Tim Stenzel: Yes. 
 

 

 

 

 

Ivory Chang: OK, good. Yeah, my question is very simple just to clarify. You mentioned about 

the home use multi-analyte OTC is not encouraged at the home test due to the multiplexing. How 

about if we put a claim as a [? presubmission ?] use only, but we will hold the test still 

multiplexing and can be distributed to non-laboratory locations like the airport, anywhere? Is this 

one can be submitted, or it's a totally no, has to become the point of care? 

Tim Stenzel: So I think you're talking about point of care testing rather than home testing, and 

we aren't limiting authorizations for point of care tests. Multi-analyte tests are fine in the point of 

care. 

Ivory Chang: OK, so which means I'm not really asking for the point of care. I'm asking can we 

put the presubmission for home use multiplexing as a product claim, or this is totally no? 

Tim Stenzel: Oh, Toby I think made that clear, right? 

Toby Lowe: You're asking if you can have a prescription home use test for multi-analyte? 

Ivory Chang: Yes. Yes. 

Toby Lowe: We would consider that. 

Ivory Chang: Oh, OK. Great. Sounds good, thank you. 

Tim Stenzel: Yep, let's move on to the next caller. Thanks. 

Elias Mallis: All right, our next call comes from Xinyi. 

Xinyi: Hello, thank you for taking my call. We are developing a neutralizing antibody test, and 

we were wondering what the FDA's review priority on that was. Thank you. 

Tim Stenzel: So we continue to make that a priority, and we have a template now on 

neutralizing test. So follow the template, submit it, and we'll review it. 

Xinyi: Thank you so much. 
 

 

 

Elias Mallis: All right, our next question comes from Laura D'Angelo. 

Laura D'Angelo: Hi, Tim and Toby. I assume you can hear me. I'm off camera. OK, anyway, so 

just in clarifying the documents that we're expecting, I thought that we were going to expect a 

guidance document on the transition, but are we going to update the templates instead or both? 

Tim Stenzel: The guidance is still going through development and/or authorization clearance for 

us to release. We don't expect that there will be an end any time soon the emergency declaration, 

nor will we stop reviewing EUAs any time soon for at least for those for which we have 

priorities. 

We are welcoming Q-subs and Presubs for the full authorization. The guidance and in fact, 

wouldn't go into-- the guidance is going to cover all potential EUA devices. And so we won't go 

into the details of what our recommendations are for individual devices that recommended 

validation. So that, we are going to provide separately as well. 

And so you don't have to wait on the guidance. You can approach us now, and as I said, our 

teams particularly for molecular have a full set of recommendations for full authorization. OK, I 

think we want to move on to another caller. I think there's a repeat caller. Maybe we could go to 

the new caller, and if we have time, go to the repeat question. 

Elias Mallis: Right. So Alex Weinberg, please ask your question. 

Alex Weinberg: Hello, can you hear me? 

Elias Mallis: Loud and clear. 

Alex Weinberg: Awesome, thank you. So in previous town halls, you've given guidance saying 

that it's OK to perform clinical studies outside of the US. Is that still the FDA's stance? 

Tim Stenzel: We would want you to start the study in the US right now for SARS. There's 

unfortunately a boatload of SARS right now. So there isn't still the need. When the volume was 

really low-- when the present positivity was really low earlier this year, we opened that up. We're 

still open to it, but we would like you to start the studies in the US because we would like to 

know how it performs in the US with US labs and/or consumers and/or point of care sites. And 

then only if you need to go outside the US that you do that, that would be our recommendation. 
 

Let's see if we can't fit in the repeat question from Melissa as well. We have two minutes 

[INAUDIBLE]. 

Elias Mallis: Melissa, the floor is yours for the last question. 

Melissa Fertiguide: OK, thank you very much. And I would like to follow up a question of a 

lady that asked before that for the high volume that could apply for that another level of priority, 

where could we submit our requests for the high volume priority, the template? 

Tim Stenzel: If you submit a sample question to the template's email address about whether or 

not your volume qualifies, that should be good enough. If you're also submitting a pre-EUA, you 

can put it in there, but you might get a quicker, more direct response just submitting that 

question. All right with that, I think we can close out today's town hall. And thank you, 

everybody. Thank you, Elias. Thank you, Toby. 

Elias Mallis: All right, thanks, Toby and Tim. This concludes today's town hall. I want to thank 

our panelists Dr. Tim Stenzel and Toby Lowe for joining us today. And I want to thank our 

audience for your participation and all the great questions that you asked our panelists today. 

Today's presentation and transcript will be available to CDRH Learn in about a week. As Tim 

said, we're working on some of the logistics involving getting the transcripts up for you. 

Please visit CDRH Learn at www.fda.gov/training/CDRHLearn. Now note that we've updated 

the title of the section to make it easier to find. You'll find the recordings at a new subsection 

titled "Coronavirus (COVID-19) Test Development and Validation Virtual Town Hall Series." 

So if you've been to CDRH Learn in the past, please check out the new listing site. 

For additional questions about today's presentation and topics, please email us at CDRH-EUATemplates@fda.hhs.gov. As we continue to hold these virtual town halls, we appreciate your 

feedback about the program series. Please complete a brief survey which you may find at 

www.fda.gov.CDRHWebinar. Again, thanks for joining us today. We'll be back with you for the 

next town hall on August 18. Take care and see you next time.