Since there are currently no FDA approved or cleared diagnostic tests to detect SARS-CoV-2,
the FDA has issued many Emergency Use Authorizations (EUAs) for the development and use of tests to detect the virus that causes COVID-19. During public health emergencies, the FDA is able to issue EUAs when certain criteria are met. These will last as long as the public health emergency lasts and then manufacturers will need to revert back to the full FDA approval process.
On 16 March 2020, the FDA released a guidance document that describes the policies to facilitate the development and use of SARS-CoV-2 diagnostic tests during the COVID-19 pandemic. This guidance document covers commercial manufacturers as well as Clinical Laboratory Improvement Amendments (CLIA) certified laboratories that meet the requirements to perform high-complexity testing.
The manufacturers and CLIA certified laboratories can begin using their tests while they prepare the EUA submission if the following are met:
- FDA notification of assay validation
- Reporting of results
- EUA request
- Clinical testing
Validation of the test should occur prior to use. This is especially important as false results can have a broad public health impact as well as affecting the individual patient. Validation of molecular tests, which are currently the most common EUA issued test method and use a sample collected via swab, includes validation studies for limit of detection, clinical evaluation, inclusivity, and cross-reactivity. Validation of serological tests, tests that use a blood sample to detect antibodies in the serum and plasma, include cross reactivity, class specificity and performance characteristics. Validation of antigen diagnostic tests, which detect SARS-CoV-2 antigens directly from clinical specimens, should include limit of detection, cross reactivity, microbial interference and performance characteristics.
FDA notification should occur after the manufacturer or laboratory has validated the test and intends to begin distribution or clinical testing. This notification should include information on testing capacity. For manufacturers this should also include a copy of the instructions for use and a summary of assay performance as well as the number of laboratories in the United States with platforms already installed. The EUA application should be completed within 15 business days of the initial FDA notification of validation completion.
Reporting of results during this interim time between test validation and EUA submission and approval should include a statement that the test has been validated but the approval from the FDA is pending. Laboratories should immediately notify the appropriate federal, state, and local public health agencies of all positive results.
EUA requests can be completed by using an FDA provided template specific for either test kit manufacturers or CLIA certified laboratories. The template facilitates the preparation, submission and authorization of an EUA. If the FDA identifies any problems with the performance data, the FDA intends to work with the laboratory to address the problem. If the FDA is not able to authorize an EUA, the FDA will notify the manufacturer or the laboratory. A manufacturer would be expected to suspend distribution and conduct a recall of the test. A laboratory would be expected to stop testing and issue corrected reports indicating that prior results may not be accurate.
While clinical testing is being carried out, the FDA recommends that the manufacturer keep instructions for use and a summary of assay performance publicly available on their website. Clinical laboratories waiting for EUA approval should confirm the first five positive and first five negative samples with an already approved EUA assay, which may involve shipping the samples to another lab.
Once the FDA has approved the EUA, the manufacturer or laboratory is able to carry out either the distribution or testing of the SARS-CoV-2 diagnostic assays. A list of current manufacturers and laboratories with approved EUAs is found on the FDA's Emergency Use Authorization page. The validation of these tests is extremely important, as it would not do any good to have an increase in tests available if the accuracy is low. Although the demand will remain high, the FDA has greatly increased the availability of tests by issuing EUAs.
Do you think the FDA’s process for issuing these devices under EUAs has been both safe and effective? What would you like to see done differently if anything?Chemistry via photopin (license)