Virtual Town Hall #76 

January 12, 2022 

Moderator: Joseph Tartal 

Joseph Tartal: Hello, and thank you for joining us today. I am Joseph Tartal, Deputy Director in the 

Division of Industry and Consumer Education in CDRH's Office of Communication Education. And I'll be 

moderating today's program. Welcome to Virtual IVD Town Hall Number 76 for SARS-CoV-2 test 

developers. This is the first for 2022, in which we'll discuss and answer your questions about diagnostic 

tests in response to COVID-19. Today's presentations and transcripts will be made available at CDRH 

Learn under the subsection titled Coronavirus COVID-19 Test Development and Validation Virtual Town 

Hall Series. 

Please note all of the previous town hall recordings and transcripts are currently posted and up to date. 

The next scheduled IVD Town Hall will take place Wednesday, January 26, 2022. 

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; Toby Lowe, 

Associate Director for Regulatory Programs in OIR; and Dr. Kristian Roth, Deputy Director of the Division 

of Microbiology Devices, also in OIR. We will begin with opening remarks from our panelists. And then 

we'll answer your previously emailed questions about COVID test development and validation. 

Please note we received some questions that are too detailed or too test case-specific that we cannot 

address on the call. For those questions, we'll try to send a response in writing within a few days. If you 

have submitted a question and do not hear it addressed, please look for the written response. If you do 

not receive one within a few days, please feel free to reach back out to the CDRH-EUATemplates@fda.hhs.gov mailbox for an update. 

Last, we'll open the line to your live questions. Right now we'll go an intro. Now I'm handing the 

program over to Tim. Welcome, Tim. 

Timothy Stenzel: Oh. Thank you, Joe. And welcome, everyone. This is an important day because we 

have a deadline coming up on Friday. So the date for labs to submit an EUA request for an LDT that they 

are currently offering without FDA authorization is January 14, this Friday. So any test developer that 

has validated an LDT test by November 15, 2021, when the new policy went into effect, we want to 

make sure that it's understood that this Friday, January 14, is the deadline. 

And you can send it to the templates email address that Joe mentioned. And I'll go into a little bit more 

detail here. And this will allow your LDT to continue to be used while the FDA reviews the application. 

There is no need to pause testing. Again, there is no need to pause testing. And if we have any questions 

about your validation, we'll be reaching out to you. And we'll be engaging you to try to work through 

those issues. All the while, you can continue testing. 

There is no test volume requirement for LDTs that are in this category. So those that have been 

validated prior to November 15, 2021, there is no volume metric recommendation. Small labs with lowvolume tests, they're fine just as well as large labs with high-volume tests. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

We did this in an effort to not decrease test availability and to allow all the LDTs that have been 

developed and launched and validated and launched in the US as of that date, which was a long time to 

take to develop a test. So we are really focusing for future submissions, not these LDT submissions that 

have not yet been submitted for EUA authorization but future review priority on those high-volume 

tests that can most impact testing access and availability. And it just makes good common sense. 

Also, all the LDTs that were on the market as well as all the tests that were notified prior to November 

15th are all in addition to the EUA tests already authorized and available for use in laboratories. So this, 

we assume, is a substantial number of tests. And since the LDTs that were validated as of November 15, 

2021, do not have to wait for an EUA authorization, this is not going to limit the testing of those 

validated tests. 

And I want to make sure that labs know - LDT developers know - just how easy it is to submit their 

validation data. It can simply be a copy, a scanned copy, a photocopy of their CLIA validation records. 

That can be your submission. Make that copy. Send it electronically to us at the template box along with 

a cover letter that says what we're doing. It's as easy as that. There should be really no problem with 

doing that for all the CLIA-validated tests out there that want to stay on the market. 

So moving to the next topic, any new EUA requests for antigen tests, we're recommending clinical data 

with omicron. This can be encompassed within the present policies or covered under the present 

policies for variant detection. We know that omicron is widespread right now. And if your validation was 

done before omicron, we really need to know how it performs with omicron, because there is the 

potential for a decrease in clinical sensitivity. There have been numerous preprints and anecdotal 

reports showing a potential loss of sensitivity here. The FDA has NIH RADx data that's suggestive of that 

as well. 

So in order to speed your process to get this data, please reach out to your FDA reviewer for ways that 

you can address this as soon as possible. Testing with actual live patient samples, even if banked as long 

as they're probably in saline, is an option to actually including omicron patients in your clinical study. 

We're not asking you to do a new clinical study. We just want to know, is the test performing on 

omicron samples? And there are multiple ways to get to that end. So we look forward to working with 

you and ensuring, through the review process and through the authorization process, that for users, for 

clinicians, for patients, they know that your test works, at least at some level, with omicron. 

Now moving to the next topic, there has been a lot of interest in the preprint data showing that saliva 

and/or other oral swabs or even oropharyngeal swabs may provide earlier detection of omicron than a 

nasal swab. And there has been discussion of use of, say, throat swabs, otherwise known as 

oropharyngeal swabs, for OTC tests and other tests, frankly, for which they have not been validated for. 

The FDA does advise that COVID-19 tests should be used as authorized, including following their 

instructions for use regarding obtaining the sample for testing. The home antigen tests available today 

are only authorized for nasal swabs. 

We have received some saliva submissions. So far, they've been unsuccessful due to performance issues. 

We do not have any data yet suggesting throat swabs are inaccurate or appropriate method for at-home 

tests. 

But we're open to receiving submissions. Of note, that saliva and throat swabs and other swabs within 

the oral cavity are different types of specimens. And they may not perform equally well. So just because 

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something works, say, for oropharyngeal doesn't mean it will work for saliva or any other sample type 

within the oropharynx. 

So we have authorized many molecular tests for saliva. But we've also seen some poor performance 

from molecular tests. And then, as I mentioned, antigen tests so far, we've looked at some that have 

been unsuccessful with saliva as a sample type for reasons unknown and could be worked out. And 

obviously, we're interested in that saliva as a sample type even for antigen tests if the issues can be 

worked out. The FDA has authorized OP swabs for some molecular tests but has not authorized them, as 

I said, for antigen tests. A check of our records, in fact, indicates that we're not aware of any 

oropharyngeal submissions or throat swab submissions for antigen tests, which the FDA, as I stated, is 

open to receiving. 

So some safety concerns. So the FDA has also noted concerns regarding self-collection of throat swabs, 

as they have been-- they are more complicated than nasal swab. Nasal swabs were ideal in many ways 

for home collection, unsupervised self-collection and, in some cases, even in some kids and, if used 

incorrectly, can cause harm to the patient. 

Some potential safety concerns may include risk of false negative, false positive results for tests that 

were not developed or validated for use with oropharyngeal specimens. And then, of course, 

oropharyngeal and/or saliva or other oral samples types may work better or worse for different variant 

types. There is evidence that OP swabs or saliva may have been worse for, say, delta than for nasal 

swab. 

So a performance may change. And having more options is great. We just like to see some data, 

including that it's an accurate way to do it and that it's safe. 

So mechanical injuries to the tonsils or throat from the swab, there are. Obvious patient preference is 

for nasal swab over getting a throat swab. Throat swabs frequently induce gagging or vomiting, which 

can lead to an aspiration of gastric contents or oral contents into the lungs, which could cause a 

pneumonia, which could complicate obviously a SARS-CoV-2 infection or other underlying lung diseases. 

And pieces as well could break off. They're more fragile. The current swabs aren't necessarily designed 

for throat swabbing. Some of them may be too short for this. And, of course, the CDC does recommend 

that throat swabs be collected by a trained health care provider. 

Moving on to the next topic. And this is the last topic before Toby goes into some notable actions and 

achievements of recent. There has been a lot of interest in genotyping tests with the increased 

prevalence of omicron and the fact that only one of the three monoclonal therapies for SARS-CoV-2 is 

active in omicron. And that is present in lower supply. Supplies are being carefully managed. 

Generally, if SARS-CoV-2 or variant results from a sequencing assay are provided to a specific patient or 

health care provider, then we would consider the assay to be a diagnostic test. And we expect the 

developer to receive an EUA for the sequencing assay prior to distribution and offering of such a test for 

clinical use. 

And, of course, it was an LDT that was validated prior to November 15, 2021. If you want to stay in the 

market with that testing, just let us know by January 14th, this Friday. Then the LDT can continue to be 

offered while the FDA reviews the EUA request. 

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As discussed in our February 2021 guidance on mutations, FDA believes that whole genome sequencing 

tests may be best suited for genotyping claims due to their ability to detect both known and emerging 

mutations and variants or otherwise unknown mutations, unknown variants that may come along. 

If you wish to pursue a genotyping claim, a detailed discussion of your validation proposal is best 

addressed within the context of a pre-EUA. We recommend that you submit a pre-EUA with a detailed 

intended use statement and validation plans for establishing performance for all mutations you find and 

detect. 

Please note that we've recommended including a diagnostic test in your genotyping test so that risk of 

false result with the genotyping test can be mitigated. Your genotyping test could be a reflex off of an 

EUA-authorized test. Or the diagnostic test can be incorporated into detection plus-minus of SARS-CoV-2 

can be incorporated into your genotyping test. 

Without a diagnostic test performed in parallel with your genotyping test, the risk to patient, due to 

false results, is significant. That makes sense. Typically, this type of significant risk is mitigated by 

providing data from a clinical validation study using samples from patients infected with virus harboring 

the mutation of interest with the diagnostic test performed in parallel. 

The risk to patients is reduced. And therefore, we will likely recommend establishing a performance of 

the genotyping test with either archives, clinical samples or inactivated virus within the clinical matrix. 

And, of course, a sequencing-based assay is probably the best comparator here if it's a good sequencing 

assay for establishing the, quote, "truth" of the genotyping result. 

Please strongly consider, with any sort of genotyping protocol, whether it be whole genome sequencing 

and/or a non-sequencing-based genotyping or a limited genotyping sequencing assay, whatever, 

submitting a change protocol with a request with your submission so that you can more easily and 

quickly update your assay without FDA review prior to launching that update as long as the preauthorized conditions for that change protocol are met. 

We, of course, are likely to want to see that data, review it in case there's any issues. But again, if you 

follow the pre-authorized change protocol, with the output conditions are met, you just go ahead and 

make that change, launch it, letting us know and showing us the validation data. You don't have to wait 

on the FDA to review. OK. Toby, I will turn it over to you now. Thank you. 

Toby Lowe: Thanks, Tim. Thanks, everyone, for joining us again this week. I'm just going to quickly run 

through a few notable actions since the last town hall. In the middle of December, we issued a letter to 

clinical laboratory staff and health care providers about false reactivity or false positives with the Rapid 

Plasma Reagin (RPR, and non-treponemal) test results with the Bio-Rad Laboratories, Bio-Plex 2200 

Syphilis Total and RPR kit in some people who have received a COVID-19 vaccine. So there's more 

information in the letter posted on our website but we just wanted to make people aware of this 

potential. 

A little bit later in December, we also added some information to the SARS-CoV-2 or Coronavirus Viral 

Mutation web page. We added information about omicron and antigen tests there. We also issued EUAs 

for the first two antigen OTC tests that had data provided through the NIH ITAP, or Independent Test 

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Assessment Program. Those were the SD Biosensor OTC COVID-19 tests distributed by Roche, and the 

Siemens CLINITEST Rapid COVID-19 test. 

And then just yesterday, we issued a safety communication regarding the LuSys Laboratories COVID-19 

antigen test and antibody tests. These tests have not been authorized, cleared, or approved by the FDA. 

And we have concerns that the performance has not been adequately established, and that there's a 

high risk of false results when using these tests. 

So I believe we can--

Joseph Tartal: Are we ready to move--

Toby Lowe: --to the questions. 

Joseph Tartal: Sure. So we'll move on to the emailed questions. Thank you to everyone who has emailed 

questions ahead of time. So again, we received some of these questions that are a little too detailed or 

test case specific that we cannot address on the call. But we will be sending a response in writing within 

a few days. Again, if you submit a question and do not hear back from us, please feel free to reach back 

out to the CDRH-EUA-Templates@fda.hhs.gov mailbox. 

So with that, we're going to get started with our first question. So Toby, would a premarket submission 

for over-the-counter COVID-19 tests be submitted as a 510(k), or would this be a De Novo? 

Toby Lowe: So we've not yet granted a full authorization for an over-the-counter COVID-19 test. So the 

first one we would likely expect to be submitted as a De Novo, and then once we offer as the first De 

Novo, subsequent similar tests would be 510(k)s. 

Joseph Tartal: OK, because that would be the predicate for the next device, perfect. So next question, 

can FDA clarify whether modifications made by a laboratory to an emergency use authorized COVID-19 

diagnostic test prior to November 15, 2021 to add new specimen types can continue to be used without 

FDA authorization? 

Toby Lowe: Yes, as long as the specimen type is one that has been previously authorized for another test 

for the same technology. This is discussed in Section 4D2 of the updated guidance. 

And it notes that for modifications made as discussed in previous versions of the guidance, prior to 

November 15, 2021, such as a high complexity CLIA-certified laboratory that modified an EUA 

authorized COVID-19 diagnostic test for use with a new specimen type, where the new specimen type 

has been previously authorized for another test of the same technology, and where the lab has 

validated the test for the new specimen type, FDA does not intend to object to the continued use--

that's continued now after the November 15 guidance-- of such a modified test without notification to 

FDA or a new or amended EUA. 

Joseph Tartal: All right. Thank you. Can FDA clarify the types of modifications that can be made by a 

laboratory to an authorized COVID-19 molecular diagnostic test after November 15, 2021? 

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Toby Lowe: Yes, so this is sort of the opposite of that previous question. And there are differences in the 

discussion in the November 15 guidance for modifications made before and after the issuance of that 

updated guidance. 

So under the modifications policy in the guidance, when a laboratory modifies an EUA authorized test 

where the laboratory has validated the modification and confirmed that the performance of the 

modified test is equivalent to the performance of the authorized test, and use of the test is limited to 

the high complexity CLIA-certified laboratory in which the modification was made, FDA does not expect 

such a laboratory to submit an EUA request for modifications that do not change the indication for use 

set forth in the EUA and also do not change the analyte-specific reagents. 

These changes can include the addition of a new or different extraction kits or instruments, since the 

addition of new or different extraction kits or instruments generally would not change the indication for 

use. Modified tests offered under this policy are offered without FDA authorization, and they should not 

include any statements that state or imply that the test is FDA authorized. This is discussed in the 

guidance, so FDA provided recommendations for transparency for such tests in Section 4.C.3 of the 

guidance. 

And then changes to the indication for use such as adding a new specimen type or a new patient 

population, such as asymptomatic individuals, would not fall under the modifications policy and FDA 

would expect a new or amended EUA be issued prior to such a test being offered. Further changes to 

the PCR primers or probes, for example, would not fall under this policy since that would involve 

changing the analyte-specific reagents. And FDA similarly, would expect a new or amended EUA be 

issued prior to such a test being offered. 

Joseph Tartal: OK, thank you for the answers of both of those questions. We'll move on to our next 

question. Our next email question, are usability in clinical studies required to support the addition of the 

mobile app for an over-the-counter antigen test? 

Toby Lowe: Yes, if you're considering a mobile app option for your device, we recommend that you 

include the mobile app as part of your usability study so that you're assessing the actual use 

environment. The entire workflow should be run by the same participants using the intended sample, 

and include the mobile app electronic instructions and result interpretation by the user in a way that's 

most consistent with how the device will be used. 

Joseph Tartal: All right. And our next question, the current test policy guidance includes priority review 

for over-the-counter and point-of-care diagnostic tests. Is FDA considering priority review for over-thecounter and point-of-care serology tests? 

Toby Lowe: So as stated in the revised guidance issued November 15, we do intend to prioritize review 

of lab-based and point-of-care serology tests that are high throughput, intended for the quantitative 

measurement of antibody titers, or the quantitative detection of neutralizing antibodies from 

developers who have indicated the ability to scale up manufacturing capacity shortly after authorization. 

Joseph Tartal: OK. For next question, can FDA clarify the clinical study patient enrollment 

recommendations to support an over-the-counter test? 

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Toby Lowe: Yeah, so we recommend that you present the symptomatic and asymptomatic data for 

over-the-counter tests both separately and combined. We generally would expect at least 20 

symptomatic individuals, and 10 asymptomatic individuals at the time of authorization. And this is 

discussed in the antigen and molecular home-use template. 

There's also information in both the molecular and antigen diagnostic test templates about the 

definition of asymptomatic individuals, which generally would be someone who's free of symptoms for 

at least two weeks prior to enrollment and testing. Or if they've previously tested positive, at least two 

weeks from the time of the last positive test prior to enrollment and testing. 

And we also would generally expect asymptomatic individuals who are suspected of COVID-19 such as 

with a known exposure be excluded from consideration as an asymptomatic individual for this context. 

And then as part of the clinical study protocol and data, we would like to see documentation of how you 

screened and confirmed that all enrolled individuals were asymptomatic and consistent with your 

proposed intended use. 

So in the EUA request, we'd like to see all of the elements of the clinical study provided including known 

exposures, symptoms, and days since symptom onset for each symptomatic individual included in the 

clinical validation study. And then we recommend that you stratify the performance data for 

symptomatic only, asymptomatic only, and then an overall combined analysis. 

Joseph Tartal: Great, thank you for that clarification. Our next question, what is FDA's position on serial 

antigen testing once per week? 

Toby Lowe: So at this time we have not seen performance data to support a weekly testing interval for 

antigen tests. In order to increase the serial testing interval to weekly for an antigen test, we would 

want to see data supporting that time interval. And we suggest that developers interested in pursuing 

this submit a proposed study design for discussion. 

Generally, we recommend that COVID-19 tests authorized for serial screening should be used as 

authorized including following the authorized instructions for use regarding repeat testing within an 

indicated time frame for asymptomatic individuals. And it's important to note that most antigen test kits 

that are authorized for screening asymptomatic individuals are authorized for serial screening typically 

over three days with at least 24 hours, and no more than 48 hours between tests. 

Joseph Tartal: All right, thank you. And this is our last emailed question. And before we go to our live 

questions, we are going to turn it back over to Tim for a minute. But this is our last emailed question. 

We received some questions about the Transition Plan guidance that was recently issued for 

transitioning after the emergency ends. Generally, do you have any clarification on how the transition 

will be implemented? 

Toby Lowe: So those guidances were recently issued, but it is premature to say what the final plan will 

be. The guidance was issued as a draft guidance and we are encouraging everyone to submit comments 

to the docket including with respect to the specific questions that were submitted for this Town Hall, as 

well as how to assure that COVID-19 tests are accurate and reliable. When the comment period closes 

on March 23, 2022, this year, we will review all the comments received and take them into 

consideration as we finalize our plans. 

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Joseph Tartal: And so please get those comments into the docket. And with that, I'm going to turn it 

over to Tim for a minute. 

Timothy Stenzel: Yeah, thank you, Joe, thank you, Toby. I see that we've had substantial numbers join us 

since the start. So I just wanted to repeat the first announcement which is very timely and there's a 

deadline of Friday, January 14 for those LDTs that want to stay on the market that had been validated 

prior to November 15, 2021, the date of the new updated guidance. There is no volume minimum for 

these LDTs. We are not interested in pulling LDTs off the market that were validated prior to November 

15th. 

It doesn't matter the volume. And the submission is very easy, just send us a copy of your CLIA 

validation. It could be photocopy, scanned copy. Send it to the template email address with a cover 

letter. That will suffice for you to get your data into us as long as it's in by this Friday, January 14, 2022. 

And for you to stay on the market, you don't need a pause while we review. You continue to meet the 

pandemic needs with your LDT while we review it. If we have questions, we'll reach back out and ask 

you, and work with you if there's any issue. We wanted all the tests that had been developed to be able 

to stay on the market while we review, so all the LDT tests. So with that, I think we can go back to the 

live questions. Thanks. 

Joseph Tartal: Sounds good thank you, Tim. So now let's take your live questions. To ask a live question, 

please select the Raise Hand icon at the bottom of your screen. When you're called on, please identify 

yourself and ask your question promptly. Also, please note that for time purposes, one question only. 

And no questions about specific submissions. So with that, our first question. I'm going to unmute you, 

Wenli. So please unmute yourself, and ask your question. 

Wenli Ja: Hello, yes, my name is Wenli Ja, and thank you for taking my question. And I have a question 

on the saliva test. And I'm from XYZ Laboratory and we are actually evaluating a saliva antigen kit, which 

has very good analytical performance. I'm sure the clinical study will follow up to see how that performs. 

And I do have a question on the PCR comparator test, I know this must have been addressed before. I 

think that with the new evidence, as Tim just mentioned, that also from our own experience, for various 

reasons we test pairs of saliva and the NP swabs sometimes for different people. 

And then what we find is at the different stages, sometimes saliva has a much higher viral content than 

the nasal swab. Sometimes the reverse, depends on the state of the patient or the infection status and 

the type. 

So with this being considered, if we still use NPS comparator test that will actually skew the data and I'm 

not sure how reliable that would be. And would the FDA consider the saliva as a comparative test? Or it 

all depends on what's the purpose right? If we use the saliva for antigen tests, then saliva as a 

comparator is just all for the assay for the self, compared to assay themselves. But if you compare 

different anatomic sites, there would be a different story. So I wonder what's the FDA thought at this 

moment, and if we can use both NP and saliva to do RT-PCR and compare with the antigen test result? 

This is my question, thank you. 

Timothy Stenzel: Thanks, Wenli. Yes, I understand your question, and I understand your concern. For 

respiratory viruses, I think most people still recognize the NP swab as the gold standard. It has been 

problematic to use in this pandemic when people need to be tested so often, but for validating a new 

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test, it does remain the gold standard. And we have seen issues with saliva for molecular tests. So that 

will still be the comparator sample type. 

You did bring up what can you do if you have discordance, particularly if the antigen test is positive and 

the NP swap should be negative. Those discordances can happen both directions. And there are ways to 

do discordant analysis up front on every sample, which can-- by using the right comparative battery of 

tests in order to adjudicate any discordances, if the proper concordant analysis testing is done on every 

sample in an unbiased fashion. That can be used to inform your PPA or NPA. 

Otherwise, if it's more focused on just the discordant samples done properly as well, we have the ability 

to annotate the 2 by 2 tables that list your performance characteristics, i.e., if the antigen test has what 

looks like false positives, compared to the NP swab, but you have a saliva test that is confirmed to be 

SARS-CoV-2, that can be a component of discordant analysis that can be placed into your instructions for 

use. 

So that is the way that we've been handling these kind of potential discordances for a long time, not just 

under this pandemic. It is a tried and true method of examining this in an unbiased way. So with this 

concern, I would discuss it with your primary reviewer, or if you are going to submit a Pre-EUA, ask it in 

the Pre-EUA submission, along with your study design and your discordant resolution design. OK? 

All right, thank you. 

Wenli Ja: Mm-hmm. 

Joseph Tartal: We'll go to our next question. Karl, I'm unmuting you. Please unmute yourself and ask 

your question. 

Karl Enters: Yes my question is for Toby. As you were discussing OTCs using an app, one of the questions 

we would have as we are developing the usability study is, must we have an actual device to do that? Or 

can we use a hybrid model where we present the screenshots and use a keypad, for instance, to 

ascertain whether it's understood and acted on appropriate. 

Toby Lowe: So we generally want to see the usability study performed as close as possible to how the 

test will be performed. So it really depends on what you're intending to use as a final product and how a 

user will interface with it. We would want to see the usability study address it that way. 

Karl Enters: OK, thank you very much. 

Toby Lowe: Mm-hmm. 

Joseph Tartal: OK, thank you. Our next question, Mark, I'm unmuting you now. Please unmute yourself 

and ask your question. 

Mark Swanson: Thank you. I had previously sent this in via email as well. So I just wanted to see if we 

can get an answer here. Can you clarify the language? I work with several clients. I'm a regulatory 

consultant working with several clients and the language has been consistent in their letters. It talks 

about notification to the Agency about authorized distributors and CLIA-certified labs. And I just want to 

know, just clarify, do they have to wait for a response from the agency before those distributors and 

labs can begin their activity? And then will FDA add them on the FDA's listings? 

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Timothy Stenzel: Mark, let me just clarify your question. You're asking for adding new distributors for a 

test, do you need to wait on FDA response? 

Mark Swanson: Correct. 

Timothy Stenzel: Yes, yes you do. We have a database of distributors some of which have known issues 

that we don't necessarily immediately approve. So it's important to run that distributor list by us and get 

our approval before doing that. 

Mark Swanson: In the CLIA-certified labs as well? 

Timothy Stenzel: I'm not sure what you mean by CLIA-certified labs? 

Mark Swanson: Well there's--

Timothy Stenzel: What do you mean? 

Mark Swanson: There's language in their EUA letter that outlines to notify the Agency of additional 

CLIA-certified labs. And they would have to wait for that response authorization to allow them to do 

that activity, correct? 

Timothy Stenzel: So if you're adding labs to an LDT sort of authorization, frequently we do want to 

review the validation for that. We have seen issues and have been unable to add labs. But it all depends 

on the original authorization and the original authorization language. For instance, some have been not 

needed. So others have been needed. So I think that's a specific enough a question depending on the 

language in the authorization to go back to your lead reviewer on that application for the greatest 

specificity of an answer. 

Mark Swanson: OK. 

Joseph Tartal: Thank you, Mark. We're going to open up the line to our next person. Venkateswaran, I'm 

unmuting you now. Please ask your question. 

Venkateswaran Kodumudi: Good afternoon. Thanks for taking my call. So my question is based on the 

revised update. The FDA is not planning to review any lab-based high volume, high throughput, high 

capacity, qualitative serology test. Is that right? 

Timothy Stenzel: At this point, the priority is for high volume point-of-care or central lab tests that can 

quantitate the level of antibody or detect neutralizing antibody. As the science has developed here on 

serology, we feel that if there's going to be an expansion of use of serology, it's going to depend on 

whether you can have an assay that detects neutralizing antibody. Or can fully quantitate, so that if 

there is an immune correlate that we can put it into international units. 

Because many of the studies that are ongoing are not using an EUA authorized tests or in this manner 

that are fully quantitative. So we need to have a way to link those study results to assays without 

requiring the assays to go ahead and do the big clinical validation for correlates to immunity. So this is 

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how we're trying to be least burdensome in applying any known correlates of immunity to serology 

tests. 

Venkateswaran Kodumudi: Thank you. 

Joseph Tartal: Our next question, Michael, I'm going to unmute. Please unmute yourself and ask your 

question. 

Are you there? Michael, please unmute yourself and ask your question. And they've dropped off. Or no? 

And go on to our next person. Meijie, please unmute yourself and ask your question. 

Meijie Tang: Hi, my question is for Toby or Tim as well. Clarify the patient enrollment about antigen 

over-the-counter test, the clinical performance study. I recall it was OK to just have 30 symptomatic at 

the time of submission, and today Toby said 20 symptomatic and the 10 asymptomatic. So is there any 

change? Or any combinations of those that will work as long, as we tabulate the performance of each 

and overall? 

Timothy Stenzel: I don't know if that is what she said. 

[BARK] 

Pardon for the dog. Kris, do you have an immediate response? I thought it was still 30 symptomatics and 

that you could go the serial testing route for asymptomatic screening without any asymptomatic 

patients. But premarket, if you wanted a single use screening test, we do want to see adequate 

performance on 10 asymptomatic samples prior to authorization. And then for subsequently, an 

additional 10 or whatever is needed to bring it up to the total of 20. Kris, can you clarify further? 

Kristian Roth: Yeah, I would agree with that. In some cases, we have-- because there's other information 

available on particular tests --we have deviated from that. But I think what Tim is mentioning is the 

standard path and I think what we continue to recommend. 

Meijie Tang: I see, so still require 30 symptomatic minimum, with or without the asymptomatic claim? 

Kristian Roth: You know, I think I would say yes. But I would say this is a very important study detail for 

you. And it might be best to follow up with an email so we're just we're absolutely sure what kind of 

claim that you're going for. If it's single use symptomatic plus a serial asymptomatic claim, if that is the 

case, then just let us know, and then we can get back you with the email with exactly what numbers 

we're expecting from that. 

Meijie Tang: Thank you. 

Joseph Tartal: Our next question is from Deb. Deb, I'm unmuting you. Please unmute yourself and ask 

your question. 

Debs Payne: Hello, everybody. Thank you so much for having these sessions. Thanks so much, Tim and 

Toby. If we use the CDC panel while it was under EUA prior to November 15th, and then we've ordered 

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primers from a different vendor where it's no longer labeled EUA, do we need to submit any paperwork 

for verification on the performance to the CDC single primer set by Friday? 

Timothy Stenzel: So you were using the SARS only CDC EUA authorized test and you were probably 

purchasing those reagents from IDT or Biosearch. Is that correct? 

Debs Payne: Correct. 

Timothy Stenzel: And that was covered under an EUA authorization. That's an interesting question, 

which we hadn't necessarily contemplated in preparation for today's call. 

Debs Payne: Yeah, so we now--

Timothy Stenzel: I think those details--

Debs Payne: Sorry. 

Timothy Stenzel: Go ahead. 

Debs Payne: So now we're just ordering the primers from IDT but they're not under EUA. Right? 

Timothy Stenzel: Yeah they're RUO and they're not quality. The previous primers that were EUA 

authorized were quality controlled by the CDC. They would do a QC check on every batch. And can you 

immediately send an email to the templates box today? And we'll sort this out offline for you, Debs. OK? 

Debs Payne: OK, thank you so much. 

Timothy Stenzel: And ask for them to copy Kris, Tim, and Toby. When they receive it they'll then share it 

to us. And we'll— 

Debs Payne: OK, yeah. 

Timothy Stenzel: --get you back a response. Because I understand your trouble and I want to try to meet 

your need here to stay on the market. 

Debs Payne: OK, thank you so much. Thank you. Sorry. 

Timothy Stenzel: Mm-hmm. 

Joseph Tartal: Thank you. I'll go to our next question from Menzelk. Menzelk, I'm unmuting you now. 

Please unmute yourself and ask your question. 

Menzelk: So, hi, can you hear me? 

Joseph Tartal: Yes, we can. 

Menzelk: OK with the new omicron variant data that Siemens was able to put into their package insert, 

how do you recommend other manufacturers that are now conducting their studies and getting their 

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results back from the NIH, can they just update their package inserts? Or do they have to send that into 

the FDA? 

Timothy Stenzel: So if the NIH has done their omicron testing on an antigen test, either an EUA 

authorized test or one that's going through one of the RADx or ITAP process, if it's pre-authorization 

we're working with RADx to put that into the labeling that we did for Siemens. But we will go through 

the antigen tests and update those labels. 

So if a particular developer, you, wants to come in and speed up that label update showing that you are 

detecting omicron, I think that's an important element due to the question about omicron performance. 

And we want to work with you on that. So if you have NIH data you can just make that request in a 

supplement, and we will work with you to get the IFU updated. 

Menzelk: Thank you. 

Joseph Tartal: OK. We'll go on to our next question, which looks like it may be our last question of the 

Town Hall. So Sunil, I'm going to unmute. Please unmute yourself and ask your question. 

Sunil Hazaray: Hello, thank you for this Town Hall meeting. And I might have misunderstood your 

answers regarding serology testing, but I just wanted to clarify if you would be accepting and reviewing 

over-the-counter serology point-of-care test submissions. 

Timothy Stenzel: So Toby said what we were prioritizing and we are not prioritizing over-the-counter 

serology tests. 

Sunil Hazaray: Thank you. 

Joseph Tartal: OK, that looks like our last question of the day. It looks like we may have had one-- Nope, 

that was it. So that is the last question of the day. So thank you, everyone. We greatly appreciate your 

participation. 

Today's program and transcript will be made available at CDRH Learn. Please visit CDRH Learn at 

www.fda.gov/training/cdrhlearn. You will find the recording and transcript in the subsection titled 

Coronavirus COVID-19 Test Development and Validation Virtual Town Hall Series. For additional 

questions about today's Town Hall and COVID-19 IVD topics in general, please email 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. Also please remember 

to join us for the next IVD Town Hall scheduled for Wednesday January 26, 2022. Hopefully see you in a 

couple of weeks. This concludes today's program. Thank you. 

********** 

END 

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