Overview of Testing for SARS-CoV-2 (COVID-19)

This document provides a summary of considerations and current Centers for Disease Control and Prevention (CDC) recommendations regarding COVID-19 testing strategies.  The CDC recommendations for COVID-19 testing have been developed based on what is currently known about COVID-19 and are subject to change as additional information becomes available.

Viral Testing

Authorized assays for viral testing include those that detect COVID-19 nucleic acid or antigen. Viral (nucleic acid or antigen) tests check samples from the respiratory system (such as nasal or oral swabs) or saliva to determine whether COVID-19 is present.  Viral tests are recommended to diagnose infection.  Some tests are point-of-care tests, often used in emergency rooms, doctor’s offices, and outpatient clinics.  These tests can produce results at the testing site in less than an hour.  Other tests must be performed in a laboratory.  If there is not a Point-of-Care (POC) device or laboratory at the collection point, samples must be sent (deliver or shipped) to a laboratory for analysis, a process that can take at least 1-2 days.

For more information on testing for COVID-19 see the Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens and Biosafety FAQs for handling and processing specimens from possible cases.

Antibody Testing

The Food and Drug Administration has not authorized antibody testing to diagnose COVID-19, and the CDC does not currently recommend using antibody testing for diagnosis of any infection.  In certain situations, antibody tests may be used in conjunction with viral detection tests to support clinical assessment of persons who present late in their illnesses.  In addition, if a person is suspected of having a post-infectious syndrome caused by COVID-19 (e.g., Multisystem Inflammatory Syndrome in Children; MIS-C), antibody tests may be used to determine prior infection.  Antibody tests for COVID-19 can play an important role in surveillance and epidemiologic studies, which can provide insights into the transmission dynamic of the virus among the general population.  Unlike direct viral detection methods that can detect currently infected persons, antibody tests help determine whether the individual being tested was previously infected, even if that person never showed symptoms.

CDC Mitigation Protocols

CDC recommends the following measures to mitigate the spread of the virus and to protect vulnerable populations:  social distancing, wearing a mask when social distancing is not possible, avoiding crowds, avoiding indoor crowded spaces, and washing or sanitizing hands frequently.  Visit cdc.gov/coronavirus for more information.

Considerations for COVID-19 Diagnostic (Molecular or Antigen) Testing

• If you have symptoms of COVID-19:
  • If your symptoms are mild:
    • Your health care provider (physician, nurse practitioner, pharmacist, etc.) may advise a COVID-19 test.
    • If you test positive for COVID-19 or do not get tested, you should self-isolate for at least 10 days after symptom onset and at least 24 hours after the resolution of any fever (without the use of fever-reducing medications).
    • You should strictly adhere to CDC mitigation protocols in circumstances in which you cannot self-isolate, especially if you are interacting with a vulnerable individual (for example an elderly person or an individual with an underlying health condition). You should adhere to CDC guidelines to protect vulnerable individuals with whom you live.
    • If you live with a vulnerable individual, they should be tested.
  • If your symptoms are severe or become severe, you should contact your health care provider immediately or seek emergency care.
  • If you take a test and test positive, you do not need to repeat a test. Unless your illness required hospitalization, you can return to normal activities (e.g., work or school) after the passage of 10 days from the onset of symptoms and 24 hours from when any fever has subsided on its own (without the aid of any fever-reducing medications).
• If you have been in close contact (within 6 feet) of a person with a COVID-19 infection for at least 15 minutes but do not have symptoms:
  • You do not necessarily need a test unless you are a vulnerable individual or your health care provider or State or local public health officials recommend you take one.
    • A negative test does not mean you will not develop an infection from the close contact or contract an infection at a later time.
  • You should monitor yourself for symptoms. If you develop symptoms, you should evaluate yourself under the considerations set forth above.
  • You should strictly adhere to CDC mitigation protocols, especially if you are interacting with a vulnerable individual. You should adhere to CDC guidelines to protect vulnerable individuals with whom you live.
• If you do not have COVID-19 symptoms and have not been in close contact with someone known to have a COVID-19 infection:
  • You do not need a test.
    • A negative test does not mean you will not contract an infection at a later time.
  • If you decide to be tested, you should self-isolate at home until your test results are known, and then adhere to your health care provider’s advice. This does not apply to routine screening or surveillance testing at work, school, or similar situations.
• If you are in a high COVID-19 transmission area and have attended a public or private gathering of more than 10 people (without widespread mask wearing or physical distancing):
  • You do not necessarily need a test unless you are a vulnerable individual or your health care provider or State or local public health officials recommend you take one.
    • A negative test does not mean you will not develop an infection from the gathering or contract an infection at a later time.
  • You should monitor yourself for symptoms. If you develop symptoms, you should evaluate yourself under the considerations set forth above.
  • You should strictly adhere to CDC mitigation protocols, especially if you are interacting with a vulnerable individual. You should adhere to CDC guidelines to protect vulnerable individuals with whom you live.
  • If you are tested, you should self-isolate at home until your test results are known, and then adhere to your health care provider’s advice.
• If you work in a nursing home or a long-term care facility:
  • You will need to be tested, unless you have already been tested as part of your facility’s operational plans.
  • You need to be tested if you are symptomatic. You must not go to work until your test results are known.  If you test positive, unless your illness required hospitalization, you can return to work after the passage of 10 days from the onset of symptoms and 24 hours from when any fever has subsided on its own (without the aid of any fever-reducing medications).
    • You will need testing if there is an outbreak in your facility (i.e., a new COVID-19 infection in any staff or any nursing home-onset of COVID-19 in a resident), and you will need to be tested at regular intervals until the outbreak has been mitigated.
  • The higher the incidence rate in the county in which you live or work, the more frequently you will need to be tested.
  • Results of testing will be used to inform infection control interventions at your facility, including decisions regarding resident placement and work exclusions.
  • Follow any additional guidance from State and local public health officials and the Centers for Medicare and Medicaid Services (CMS).
• If you live in or receive care in a nursing home or a long-term care facility:
  • You will need to be tested, unless you have already been tested as part of your facility’s operational plans.
  • You need to be tested if you are symptomatic. You must self-isolate until your test results are known.  If you test positive, unless your illness required hospitalization, you can return to normal activities after the passage of 10 days from the onset of symptoms and 24 hours from when any fever has subsided on its own (without the aid of any fever-reducing medications).
  • You will need testing if there is an outbreak in your facility and you will need to be tested at regular intervals until the outbreak has been mitigated.
  • You will need to be tested more frequently if you leave the facility on a regular basis (e.g. for dialysis or frequent medical/other appointments).
  • Results of testing will be used to inform infection control interventions at your facility, including decisions regarding resident and patient placement.
  • Follow any additional guidance from State and local public health officials and the CMS.
• If you are a critical infrastructure worker, health care worker, or first responder:
  • You may need to get a test, according to your employer’s guidelines.
  • Even if you have a negative test, you should, at all times, take special care to monitor yourself for symptoms and strictly adhere to CDC mitigation protocols.
• State and local public health officials may advise specific people, or groups of people, to be tested. You should follow this advice.
• It is important to realize that you can be infected and spread the virus but feel well and have no symptoms.
  • In areas where there are limited number of new cases, State or local public health officials may request to test a small number of asymptomatic “healthy people,” particularly from vulnerable populations.
  • If there is significant spread of the virus in your community, State or local public health officials may request to test more asymptomatic “healthy people,” particularly from vulnerable populations.
  • For example, certain settings can experience rapid spread of COVID-19. This is particularly true for settings with vulnerable populations in close quarters for extended periods of time (e.g., hospitals, nursing homes, and long-term care facilities).
    • As discussed above, those responsible for managing infection in such settings should adopt measures to facilitate the early identification of infected individuals, including initial testing of everyone in the setting, periodic (e.g., weekly) testing of everyone in the setting, and testing of new or returning entrants into the setting.