COVID-19 and Diagnostics
Rapid detection of COVID-19 cases in the United States requires widespread availability of testing. On February 4, 2020, the Secretary of Health and Human Services determined that there is a public health emergency and that circumstances exist justifying the authorization of emergency use of unapproved in vitro diagnostics for detection and/or diagnosis of the novel coronavirus.
In vitro diagnostics are tests performed on samples taken from the human body, such as swabs of material from inside the nose or back of the throat or blood taken from a finger prick or drawn by a phlebotomist. In vitro diagnostics can detect diseases or other conditions and be used to monitor a person's overall health to help cure, treat, or prevent diseases. (To learn about testing strategy and diagnostics, please visit our Diagnostics Evidence Accelerator.)
The term "diagnostic test" is generally used to refer to molecular or antigen tests, both of which can be used to diagnose infection with the SARS-CoV-2 virus.
Molecular tests identify the virus in samples from the respiratory system and can be used to diagnose illness. Molecular tests include PCR (polymerase chain reaction) tests, which are considered to be the most accurate.
Antigen tests detect the presence of viral proteins found on the surface of the SARS-CoV-2 virus. Several point of care antigen tests for SARS-CoV-2 have been issued an Emergency Use Authorization (EUA). These tests use specimens taken from nasal swabs. Emergency use of most of these tests is limited to authorized laboratories and other authorized testing locations.
Some tests must be sent to a laboratory for analysis, a process that may take one or more days once the lab receives your samples. Some tests are conducted at the testing site you visit with results available to you within minutes. Some tests are authorized for use at home.
Serology or Antibody Tests
The terms "serology" or "antibody" generally refer to blood tests that detect antibodies to the SARS-CoV-2 virus. Because the antibodies are part of the body's immune response to exposure and not the virus itself, such testing should not be used to diagnose infection but can help identify whether an individual has had an adaptive immune response to SARS-CoV-2. Such a response would indicate recent or prior infection by detecting antibodies to SARS-CoV-2 in human blood specimens. Researchers are working to determine if the antibodies indicate immunity to the virus, and if so, how long that protection from reinfection might last. For additional performance information about EUA authorized serology/antibody tests, please see the EUA Authorized Serology Test Performance webpage.
Regulation of Tests
The U.S. Food and Drug Administration is responsible for regulating medical devices such as diagnostic tests. During this emergency, some tests have been issued Emergency Use Authorizations.
Tests, and the laboratories that run tests, vary in level and complexity. Complex tests must be performed in a laboratory certified to perform high-complexity or moderate-complexity testing under the Clinical Laboratory Improvement Amendments (CLIA). Others can be performed in patient care settings (such as one in a primary care office) operating under a CLIA Certificate of Waiver, Certificate of Compliance, or Certificate of Accreditation, and some tests are even authorized for use at home. FDA maintains a table of tests that have been issued Emergency Use Authorizations, where tests authorized for use in point-of-care settings are indicated with a W and those authorized for use at home are indicated with “Home.”
You will also see tests marked as M and H, representing tests that are authorized for use in Moderate Complexity and High Complexity labs. As tests become more complex, so do the labs that process the tests. These designations basically let you know that those tests require more specialized handling, which may include higher levels of training, materials/equipment, experience, and proficiency. In some cases, the High Complexity labs may be using a test they developed themselves.
Use the links below to learn more about diagnostics and testing.
A Closer Look at COVID-19 Diagnostic Testing – A webpage to provide health care providers and other public health professionals information about different types of tests
COVID-19 Testing: Rapid Acceleration of Diagnostics – NIH launches the Rapid Acceleration of Diagnostics (RADxSM) initiative to speed innovation of COVID-19 testing
Chembio EUA – FDA revokes Emergency Use Authorization for Chembio antibody test
Emergency Use Authorizations – Lists current and terminated EUAs that make available diagnostic and therapeutic medical devices to respond to public health emergencies
EUA for Self-Testing at Home – FDA authorizes first COVID-19 test for self-testing at home
EUA Authorized Serology Test Performance – FDA summarizes expected performance of authorized tests
EUA for Point of Care Antigen Test – FDA has issued three EUAs for COVID-19 antigen diagnostic tests
FAQs on Testing for SARS-CoV-2 – FDA answers questions about SARS-CoV-2 testing
FDA Voices – FDA explains ongoing work to support and advance COVID-19 diagnostic test accuracy and availability
In Vitro Diagnostics EUA Templates – FDA updates templates for laboratories and commercial manufacturers to help facilitate submission of EUA requests
Laboratory Safety – CDC's guidance for lab safety while handling COVID-19 specimens and equipment
Letter to Clinical Laboratory Staff and Health Care Providers – FDA alerts of potential for false positive results with antigen tests for rapid detection of SARS-CoV-2 -
Medical Devices and the COVID-19 Pandemic – Information from FDA about medical devices used to diagnose, prevent, and treat COVID-19
NIH Treatment Guidelines
- Potential antiviral drugs under evaluation for the treatment of COVID-19
- Testing information on SARS-CoV-2 infection
Policy for Coronavirus Disease-2019 Tests – Immediately in effect guidance from FDA for clinical laboratories, commercial manufacturers, and FDA staff
Rapid Antigen Testing – CDC's Interim Guidance for Rapid Antigen Testing for SARS-CoV-2
Testing Overview - CDC's overview of all matters related to COVID-19 testing