COVID-19 Test Development and Review: FAQs on Testing for SARS-CoV-2
This page provides answers to frequently asked questions related to COVID-19 test development and review.
This section includes questions and answers regarding the policies outlined in the Immediately in Effect Guidance for Clinical Laboratories, Commercial Manufacturers, and Food and Drug Administration Staff: Policy for Coronavirus Disease-2019 Tests during the Public Health Emergency (Revised). In this section, this guidance is referred to as the Policy for Coronavirus Disease-2019 Tests.
For a directory of FAQs related to SARS-CoV-2 testing, see FAQs on Testing for SARS-CoV-2.
A: We are currently in a different phase of the pandemic with respect to tests than we were previously, where many COVID-19 tests are now authorized. We prioritize review of EUA requests for tests taking into account a variety of factors, as discussed in the Emergency Use Authorization of Medical Products and Related Authorities Guidance, such as the public health need for the product and the availability of the product. We have, for example, prioritized review of EUA requests for tests where authorization would increase testing accessibility (e.g., point of care (POC) tests, home collection tests, and at-home tests) or would significantly increase testing capacity (e.g., tests that reduce reliance on test supplies and high-throughput, widely distributed tests).
A: During this unprecedented public health emergency, the Agency has received an exceedingly high volume of EUA requests and is working as quickly as possible to review each request. There are hundreds of pre-EUA and EUA requests for COVID-19 tests under review and FDA continues to receive new submissions on a daily basis. To address this high volume of work, we have brought in additional scientific review staff to double the number of teams working on submissions; and we have implemented a triage program to prioritize submissions based on several factors. As a result of these efforts, by November 1, 2020, FDA had authorized over 285 diagnostic and serology tests, far exceeding the number of test EUAs issued during previous emergencies.
As explained in FDA's guidance "Emergency Use Authorization of Medical Products and Related Authorities," starting on page 18, FDA prioritizes EUA requests based on several factors that include, but are not limited to, the public health need of the product (e.g., point-of-care; high throughput), the extent to which the product would serve a significant unmet medical need (e.g., at-home specimen collection; at-home testing), and the availability and adequacy of the information concerning the likelihood that the product may be safe and effective in preventing, treating, or diagnosing the condition, as well as the availability of the product (e.g., the quantity and manufacturing capacity).
FDA strives to review Pre-EUA and EUA requests as quickly as we can. FDA will communicate with each sponsor regarding its pre-EUA or EUA request as soon as possible. The review team will be in contact with you when its review is complete or if there are questions. If you have not yet been assigned a lead reviewer for your pre-EUA or EUA request, we recommend that you refer to the available resources to help you with your planning and submitting your EUA request:
- SARS-CoV-2 IVD EUAs (Letters of Authorization and Instructions for Use/EUA Summaries)
- EUA Templates with recommendations to help facilitate EUA requests, as explained in the Policy for Coronavirus Disease-2019 Tests
- FAQs on Testing for SARS-CoV-2
A: With appropriate mitigations and validation, FDA believes that sample pooling can be safely implemented for use in certain diagnostic and screening tests. If you would like to develop and offer a test for use with sample pooling, please see the EUA templates for recommendations on how to validate the test for this use and submit your EUA request to the FDA.
As discussed in the templates, there are currently two approaches to patient specimen pooling: 1) pooling aliquots of transport media each containing a single patient sample (sample/media pooling) or 2) adding swabs from multiple patients into a single volume of transport media (swab pooling). These templates include validation recommendations for both types of pooling approaches.
Generally, FDA recommends validating your test with either pooling approach in a way that preserves the sensitivity of your test as much as possible; that is, it is preferable to use an approach where all specimens identified as positive when tested individually are also identified as positive when tested using the pooled testing approach. However, a decrease in performance is likely with pooling strategies, due to dilution of the primary clinical sample. As discussed in the templates, since sample pooling will greatly increase the number of individuals that can be tested using existing resources, a small reduction in sensitivity may be acceptable depending on the pooling efficiency and other mitigations in place. Therefore, FDA generally recommends that, after pooling, test performance includes ≥85% percent positive agreement (PPA) when compared with the same test performed on individual samples. Additional limitations, such as considering negative results from pooled samples to be presumptive negatives, may be recommended based on the patient population included in your clinical evaluation and the performance data submitted in your EUA request.
As discussed in the templates, ongoing monitoring of the positivity rate and of the performance of a test with a pooling strategy is an important mitigation and should be included in test labeling. As data become available and new approaches are identified, our recommendations in these templates may evolve.
The Policy for Coronavirus Disease-2019 Tests explains FDA's regulatory flexibility regarding developers that offer validated diagnostic tests, including for use with sample pooling, while the developers pursue an EUA from the FDA.
A: The Rapid Acceleration of Diagnostics (RADx) program, supported by the National Institutes of Health (NIH) National Institute of Biomedical Imaging and Bioengineering (NIBIB), has suspended the RADx Fast-Track Program for COVID-19 Test Development and Distribution submission portal and is currently not accepting new applications. Additional information, including potential alternate funding opportunities, can be found on the Rapid Acceleration of Diagnostics (RADx) website.
A: Yes. FDA values collaboration between developers to reduce the burden for test validation. A developer that has provided data to the FDA may grant a right of reference to other developers, either broadly or to individual developers, to leverage that data. In these cases, if the data is applicable to the new developer's test, they would generally not have to repeat that validation for their submission to the FDA. For example, if a new developer's test is similar to the CDC assay, they may be able to leverage the CDC's in silico and cross reactivity data, rather than repeating it. Further, as discussed in another FAQ on this page (Can I offer my test for self-collection of a specimen at home and shipping to a laboratory for testing?), FDA has reviewed analytical validation data from a swab stability study conducted by Quantigen Biosciences, with support from The Gates Foundation and UnitedHealth Group, that can be used, in conjunction with other data from the developer, to support sample stability of foam or polyester nasal swabs shipped dry or in saline for testing with authorized SARS-CoV-2 molecular diagnostic assays.
Any developer seeking to leverage data from an EUA-authorized assay must obtain a right of reference from the sponsor of that EUA.
The CDC has granted a right of reference to the performance data contained in the CDC's EUA request for the CDC 2019-nCoV Real-Time RT-PCR Diagnostic Panel (CDC) (FDA submission number EUA200001) to any entity seeking an FDA EUA for a COVID-19 diagnostic device.
The CDC has granted a right of reference to the performance data contained in the CDC's EUA request for their Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay (FDA submission number EUA201781) to any entity seeking an FDA EUA for a multi-analyte respiratory panel that includes SARS-CoV-2. CDC has published the primer and probe sequences for the Influenza SARS-CoV-2 Multiplex Assay on the CDC website.
A: FDA has provided recommendations regarding validation testing for SARS-CoV-2 tests in the EUA templates referenced in the Policy for Coronavirus Disease-2019 Tests and provided for download from the FDA website. These recommendations include the testing that should be performed to demonstrate that a SARS-CoV-2 test is validated based upon the underlying technological principles of the test, as well as generally expected performance metrics. These recommendations for testing apply to tests for which an EUA request is submitted to FDA as well as tests claiming to be validated and offered under the policies in the Policy for Coronavirus Disease-2019 Tests prior to submission of an EUA request. Depending on the characteristics of your test, additional validation studies may be recommended. FDA encourages test developers to discuss any alternative approaches to validating their test with FDA through CDRH-EUA-templates@FDA.HHS.GOV.
The EUA Templates reflect FDA's current thinking on the data and information that developers should submit to facilitate the EUA process. The templates provide information and recommendations, and we plan to update them as appropriate as we learn more about the COVID-19 disease and gain experience with the EUA process for the various types of COVID-19 tests.
Developers can use alternative approaches. Developers who intend to use alternative approaches should consider seeking FDA's feedback or recommendations to help them through the EUA process. FDA encourages developers to discuss any alternative approaches with FDA through CDRH-EUA-Templates@fda.hhs.gov.
A:We encourage developers to first review the available resources, including the EUA templates, the FAQs on this webpage, and the Letters of Authorization and Instructions for Use/EUA Summaries from previously authorized tests (SARS-CoV-2 IVD EUAs). If you have additional questions or want to discuss novel approaches that are not addressed in the EUA templates and previous authorizations, please reach out to us at CDRH-EUA-Templates@fda.hhs.gov to begin pre-EUA discussions, even if you do not have your validation and/or documentation completed.
A: Below is information regarding various test materials for diagnostic assay validation. Links provided are for information purposes only and are not a recommendation by FDA to use that product. FDA encourages other suppliers of test materials to email COVID19DX@fda.hhs.gov to discuss whether materials they have available may also be appropriate for use.
As noted in the molecular diagnostic templates, FDA recommends using natural clinical specimens in the clinical evaluation for those tests. Please refer to those EUA templates for information regarding clinical study design for molecular diagnostic tests. If you do not have access to positive clinical samples from a clinical laboratory, these are available commercially:
- Boca Biolistics: Order by emailing COVID19support@BocaBio.com
- Product # C0040-0001: SARS-COV-2 Validation Panel
- This product includes 30 positive patient samples and 30 negative patient samples, as determined by CLIA-certified labs.
- Product # C0040-0001: SARS-COV-2 Validation Panel
- Discovery Life Sciences: Order by emailing sales@dls.com OR following the instructions on their COVID-19 website links below:
- Product: Discovery COVID-19 Remnant Biospecimen Sets
- Discovery Life Sciences has positive and negative patient specimens, as determined by CLIA-certified labs, for several remnant biospecimen types. Contact them to discuss options.
- Product: Fully Consented Matched Biospecimen Sets
- Matched sets can include Plasma, Serum, PBMCs and Saliva with comprehensive patient data available.
- Product: Discovery COVID-19 Remnant Biospecimen Sets
As also noted in the molecular diagnostic templates, in the absence of known positive samples, Limit of Detection (LoD) validation studies may also be performed with contrived clinical specimens. Live cultured virus preparation, virus culture lysate (both require BSL-3 biosafety containment), or inactivated virus (e.g., heat treated, irradiated, or chemically modified virus, which only require BSL-2 biosafety containment) are acceptable materials to generate contrived specimens since this most closely reflects live virus in a clinical sample. You may request inactivated virus directly from:
- BEI Resources: Order through BEI Resources website
- Product # NR-52286: SARS-Related Coronavirus 2, Isolate USA-WA1/2020, Heat inactivated
- Product # NR-52287: SARS-Related Coronavirus 2, Isolate USA-WA1/2020, Gamma-Irradiated
- ATCC: Order through their Coronavirus Resources website
- Product # VR-1986HK: Heat-inactivated SARS-CoV-2 (strain 2019-nCoV/USA-WA1/2020)
- ZeptoMetrix: Order by emailing custserv@zeptometrix.com OR calling customer service at 1-800-274-5487 OR through their website
- Product # NATSARS(COV2)-ERC: NATtrol SARS-Related Coronavirus 2 (SARS-CoV-2) External Run Control (6 X 0.5mL)
- This product contains approximately 50,000 copies/mL. The isolate is USA-WA1/2020, chemically inactivated.
- Product # NATSARS(COV2)-ST: NATtrol SARS-Related Coronavirus 2 (SARS-CoV-2) Stock (1mL)
- This product contains approximately 1,000,000 copies/mL. The isolate is USA-WA1/2020, chemically inactivated.
- Product # NATSARS(COV2)-ERC: NATtrol SARS-Related Coronavirus 2 (SARS-CoV-2) External Run Control (6 X 0.5mL)
A: Yes. Given the overlap in signs and symptoms between SARS-CoV-2 and other respiratory viral infections, including influenza, FDA has authorized multi-analyte respiratory panels for the qualitative detection and differentiation of nucleic acid from multiple pathogens, including the SARS-CoV-2 virus. These panels are useful when multiple respiratory pathogens are circulating at the same time, as is expected with the upcoming flu season. The ability to run one test to identify which pathogen is present provides faster results overall and more efficient use of resources.
When determining whether to issue an EUA for a multi-analyte respiratory panel, FDA considers, among other things, the use of the test (multi-analyte pathogen detection as an aid in differential diagnosis), clearance/approval status of IVDs for the other panel members, whether the proposed Intended Use fits within the HHS emergency declaration and how the panel test would fit into current recommendations of public health authorities regarding patient testing.
If you would like to develop and offer a multi-analyte respiratory panel that includes SARS-CoV-2, please see the EUA templates for recommendations on how to validate the test for this use and for recommendations on what to include in your EUA request to the FDA.
Please note that the policies in the Policy for Coronavirus Disease-2019 Tests do not apply to multi-analyte respiratory panels, and the FDA expects developers of such tests to request and receive an EUA prior to offering or marketing their test.
The CDC has granted a right of reference to the performance data contained in the CDC's EUA request for their Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay (FDA submission number EUA201781) to any entity requesting an EUA for a multi-analyte respiratory panel that includes SARS-CoV-2. CDC has published the primer and probe sequences for the Influenza SARS-CoV-2 Multiplex Assay.