Antigen Screening Information
How is Bates using rapid antigen tests?
Bates is currently using rapid antigen tests as a screening tool for students upon arrival and once a week during the weekly testing cycle. This allows Bates to quickly separate individuals with potential COVID-19 from the remainder of the student population. We are doing all we can to limit transmission of disease once students arrive on campus by engaging the most up-to-date screening and diagnostic tests available.
It is not until a rapid antigen test is coupled with a positive PCR test result that a person may be considered an active asymptomatic case of COVID-19.
What is the difference between screening and diagnostic testing?
“Screening refers to the use of simple tests across an apparently healthy population in order to identify individuals who have risk factors or early stages of disease…” -World Health Organization. Bates is currently using the rapid antigen test as a screening tool.
Diagnostic tests refer to the ability of a test to more accurately diagnose the presence of a disease, or rule one out. Bates is currently using the Broad RT-PCR test as our diagnostic test.
What is an antigen test?
Antigen tests are a specific type of indicator of COVID-19 that can detect certain proteins that are part of the SARS-CoV-2 virus.
How does it work?
The tests are collected using secretions from the nose or throat. This fluid sample is tested for active viral proteins.
What is a rapid antigen test?
Rapid antigen tests can be used for surveillance and screening of active disease; results are available within 30 minutes. They are only used to rule out COVID-19 in high-risk populations such as those living in congregate housing. These rapid tests can quickly identify if a person has viral particles that are related to SARS-CoV-2 infection. When used with additional PCR (molecular) tests, rapid antigen tests can provide preliminary data about the presence or absence of disease quickly.
Can antigen tests diagnose COVID-19?
Depending on the clinical scenario, an antigen test can diagnose COVID-19; however, this is only when a patient is experiencing classic symptoms of the disease. Otherwise antigen tests are used as a tool in surveillance screening of asymptomatic individuals to rule out disease with COVID-19 – as Bates is doing for arrival screening and once per week. In asymptomatic individuals, an initial positive antigen test is not diagnostic by itself and is typically repeated and also confirmed with a PCR (molecular) test.
Are antigen tests accurate?
Positive results can be accurate, especially if an immediately issued second antigen test is also positive or if the patient has symptoms of COVID-19. However, false positives can happen, especially in areas without high prevalence of disease. That is why it is imperative to couple antigen tests with PCR (molecular) tests to diagnose COVID-19 in asymptomatic individuals. It is not until a rapid antigen test is coupled with a positive PCR test result that a person may be considered an active asymptomatic case of COVID-19.
Why are antigen tests used?
Antigen tests with rapid results offer a unique approach to screening and surveillance in scenarios where there may be high risk of disease spread (such as congregate housing, hospitals, and nursing homes). When rapid antigen tests are used, results are available in 30-60 minutes and can help quickly stop the spread of disease. These tests help to identify those people who may be asymptomatic or early on in a disease course.