Rapid antigen coronavirus tests are just as accurate as laboratory tests when used every three days, a new study from the National Institutes of Health (NIH) finds.
Both test types caught 98 percent of COVID-19 cases, the researchers found through regularly testing college students and staffers at the University of Illinois.
Antigen tests detect proteins found on the surface of the virus, rather than genetic material, which is what laboratory, or polymerase chain reaction (PCR), tests look for.
PCR tests have traditionally been considered more accurate at identifying cases when a patient is further along in their disease progression.
However, swabs need to be sent to a laboratory and take two to three tests for results to return where as rapid antigen take just 15 minutes to return.
When test frequency goes down to once a week, researchers found antigen tests catch only 80 percent of cases.
The study suggests that antigen tests may be invaluable in schools, workplaces, and other settings during future COVID-19 outbreaks.
Antigen tests are cheaper and produce results quickly - making them perfect for screening programs. Pictured: A woman gets swabbed for an antigen test in Lisbon, Portugal
When used frequently, antigen tests are just as effective as PCR tests, the NIH study found
If people need to get COVID-19 test, PCR tests are the gold standard.
These tests are highly accurate because they look for specific genetic material matching the coronavirus in a sample from someone's mucus or saliva.
However, PCR tests are expensive and may be time consuming.
In the early months of the pandemic, some Americans who got PCR tests had to wait over a week for their results - and even now, wait times may be two days or more.
During that wait, the coronavirus can continue spreading undetected.
As a result, many public health experts promote antigen tests - rapid tests that look for proteins in the surface of the coronavirus.
Antigen tests are cheap, easy to administer, and can be performed in a doctor's office, at school, or even at home - and results may be delivered in under 15 minutes.
Antigen tests come with a downside, though - they are not as accurate as PCR tests.
These tests have a lower sensitivity, meaning that those who get tested with antigen tests are more likely to be false negatives - receiving a negative result even though they're actually infected.
However, past modeling studies have shown that, when antigen tests are used frequently, that repeated use will catch the majority of Covid cases in a community.
The NIH researchers conducted this study, with results published in The Journal of Infectious Diseases, at the University of Illinois, which was already using frequent testing to identify cases on campus.
When a student or staff member
