COVID-19 Testing Guidelines

Introduction to COVID-19 Testing

A negative COVID-19 test result does not definitively prove that a person is not infectious, as tests can miss active infections and viral RNA detection does not perfectly correlate with infectiousness 1
The Infectious Diseases Society of America (IDSA) states that they were "unable to find definitive evidence demonstrating that a negative NAAT result following a positive result is proof that a patient is no longer infectious" 1

NAAT (Nucleic Acid Amplification Tests, including PCR) and antigen tests detect the presence of SARS-CoV-2 RNA or proteins, but this detection does not perfectly correlate with infectiousness 1
Antigen tests have approximately 82% sensitivity, which is lower than molecular tests 2
False negative results can occur due to timing of the test, improper sample collection, and test sensitivity limitations 2

If a person has symptoms consistent with COVID-19 but tests negative, especially with an antigen test, consider confirmatory testing with a molecular test (PCR) and continue isolation precautions if clinical suspicion remains high 2
The IDSA panel suggests using standard NAAT (PCR) over rapid antigen tests for symptomatic individuals 2
A negative test does not immediately rule out infection if there has been a known exposure, and many factors beyond test results affect transmission risk, including immune status, vaccination history, mask usage, and ventilation of shared spaces 1

The IDSA recommends against using repeat negative tests to guide release from isolation 1
A symptom-based approach is preferred over a test-based approach for discontinuing isolation precautions, considering factors such as immune status, vaccination history, and exposure duration 1
Home tests have lower sensitivity than laboratory tests, particularly early in infection, and overreliance on home testing can lead to false confidence and contribute to virus spread 3

A negative test is not a "passport" to abandon precautions, especially if symptomatic, and maintaining precautions despite a negative test is the safest approach 1
The "test of cure" concept for COVID-19 has not been verified, and abandoning precautions too early can contribute to virus spread 1