Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
UPDATE
Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.
UPDATE
The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.
UPDATE
Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

Testing Strategies for SARS-CoV-2

Testing Strategies for SARS-CoV-2
Updated Aug. 13, 2021

Summary of Recent Changes

Key Points

  • This guidance describes and compares different types of testing strategies SARS-CoV-2 (the virus that causes COVID-19), including their intended use and applications, regulatory requirements, and reporting requirements.
  • This guidance is intended for those who offer and perform SARS-CoV-2 testing.
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COVID-19 Viral Testing Tool

A tool to help healthcare providers quickly access the most relevant, actionable information to determine what type(s) of COVID-19 testing they should recommend. After test results are in, the tool can help interpret test results and guide next steps.

Diagnostic Testing

Diagnostic testing is intended to identify current infection in individuals and should be performed on anyone that has signs and symptoms consistent with COVID-19. A laboratory-based Nucleic Acid Amplification Test (NAAT) is recommended for diagnostic testing of vaccinated, asymptomatic individuals following recent known or suspected exposure to SARS-CoV-2.

Examples of diagnostic testing include:

  • Testing anyone with symptoms consistent with COVID-19
  • Testing vaccinated and unvaccinated people who were exposed to someone with a confirmed or suspected case of COVID-19

Screening Testing

Screening tests are intended to identify unvaccinated people with COVID-19 who are asymptomatic and do not have known, suspected, or reported exposure to SARS-CoV-2. Screening helps to identify unknown cases so that measures can be taken to prevent further transmission.

Examples of screening include testing:

  • Employees in a workplace setting
  • Students, faculty, and staff in a school setting
  • A person before or after travel
  • Someone at home who does not have symptoms associated with COVID-19 and no known exposures to someone with COVID-19

Public Health Surveillance Testing

Public health surveillance is the ongoing, systematic collection, analysis, and interpretation of health-related data essential to the planning, implementation, and evaluation of public health practice. See CDC’s Introduction to Public Health Surveillance.

Public health surveillance testing is intended to monitor community- or population-level outbreaks of disease, or to characterize the incidence and prevalence of disease. Surveillance testing is performed on de-identified specimens, and thus, results are not linked to individual people. Public health surveillance testing results cannot be used for individual decision-making.

Public health surveillance testing may sample a certain percentage of a specific population to monitor for increasing or decreasing prevalence, or to determine the population effect from community interventions such as social distancing. An example of public health surveillance testing is when a state public health department develops a plan to randomly select and sample a percentage of all people in a city on a rolling basis to assess local infection rates and trends.

Regulatory Requirements for Diagnostic, Screening, and Public Health Surveillance Testing

Any laboratory or testing site that performs diagnostic or screening testing must have a Clinical Laboratory Improvement Amendments (CLIA) certificate and meet all applicable CLIA requirements. For more information, see the Centers for Medicare & Medicaid Services CLIA websiteexternal icon. Tests used for SARS-CoV-2 diagnostic or screening testing must have received an Emergency Use Authorization from the U.S. Food and Drug Administration (FDA) or be offered under the policies in FDA’s Policy for COVID-19 Testsexternal icon.

Tests used for SARS-CoV-2 public health surveillance on de-identified human specimens do not need to meet FDA and CLIA requirements for diagnostic and screening testing.

Reporting Diagnostic, Screening, and Public Health Surveillance Testing Results

Both diagnostic and screening testing results should be reported to the people whose specimens were tested and/or to their healthcare providers.

In addition, laboratories that perform diagnostic and screening testing must report test results (positive and negative) to the local, state, tribal, or territory health department in accordance with Public Law 116-136, § 18115(a), the Coronavirus Aid, Relief, and Economic Security (CARES) Act. The Department of Health and Human Services published guidance on COVID-19 Pandemic Response, Laboratory Data Reporting: CARES Act Section 18115pdf iconexternal icon that specifies what data, in addition to test results, laboratories and testing sites should collect and electronically report.

Public health surveillance testing results cannot be reported directly to the people whose specimens have been tested and are not reported to their healthcare providers. Public health surveillance testing results (test results that are de-identified) can be reported in aggregate to local, state, tribal, or territory health departments upon request. Results from testing that is performed outside of a CLIA-certified facility or without an FDA-authorized test can only be reported to a health department if those results are used strictly for public health surveillance purposes, and not used for individual decision making.

Summary of Testing Strategies for SARS-CoV-2

Diagnostic

Screening

Public Health Surveillance

Symptomatic

Diagnostic

Yes

Screening

No

Public Health Surveillance

N/A

Unvaccinated or vaccinated with known or suspected exposure to SARS-CoV-2

Diagnostic

Yes

Screening

No

Public Health Surveillance

N/A

Unvaccinated and Asymptomatic without Known or Reported Suspected Exposure to SARS-CoV-2

Diagnostic

No

Screening

Yes

Public Health Surveillance

N/A

Characterize Incidence and Prevalence in the Community

Diagnostic

N/A

Screening

N/A

Public Health Surveillance

Yes

Testing of Personally Identifiable Specimens

Diagnostic

Yes

Screening

Yes

Public Health Surveillance

No

Results may be Returned to Individuals

Diagnostic

Yes

Screening

Yes

Public Health Surveillance

No

Results Returned in Aggregate to Requesting Institution

Diagnostic

No

Screening

No

Public Health Surveillance

Yes

Results Reported to State Public Health Department

Diagnostic

Yes

Screening

Yes

Public Health Surveillance

If requested

Testing can be Performed in a CLIA-Certified Laboratory

Diagnostic

Yes

Screening

Yes

Public Health Surveillance

Yes

Testing can be Performed in a Non-CLIA-Certified Laboratory

Diagnostic

No

Screening

No

Public Health Surveillance

Yes

Test System Must be FDA Authorized or be Offered under the Policies in FDA’s Guidance

Diagnostic

Yes

Screening

Yes

Public Health Surveillance

No