Rapid home COVID-19 tests detect nearly as many infections as lab tests, study shows
- A new study compared the accuracy of rapid antigen testing to lab PCR testing in detecting COVID-19 testing
- The rapid test looks for antigens, proteins found on the surface of the virus, rather than genetic material
- When used twice a week, the rapid tests correctly identified 15 out of 15 Covid cases and detected 96% of cases with three days of symptoms
- Researchers say the faster, cheaper antigen tests could be used for screening programs in schools, workplaces and other settings
Rapid COVID-19 antigen tests are almost as accurate as lab tests at detecting infections when used twice a week, a new study suggests.
Researchers found that the rapid home test was able to detect all 15 cases of Covid and 96 percent of samples within three days of infection
Antigen tests look for proteins found on the surface of the virus compared to the virus’s genetic material, which is what lab tests detect.
Traditionally, lab tests have been considered more accurate in detecting Covid cases.
However, it often takes two to three days for sample results to be returned, while rapid antigen testing often provides results in as little as 15 minutes.
The team — made up of researchers from Harvard TH Chan School of Public Health and Mount Sinai School of Medicine — say the cheaper, simpler test could be used as part of screening programs in workplaces, schools and other settings.
A new study found that rapid Covid tests (above) with twice-weekly use correctly identified 15 out of 15 Covid cases and detected 96% of cases with three days of symptoms
Laboratory testing, also known as polymerase chain reaction (PCR) testing, is considered the gold standard in COVID-19 testing.
They are considered very accurate because they detect coronavirus genetic material in a patient’s mucus or saliva.
However, they are expensive and have a long lead time because the sample must be sent to a lab and analyzed by a professional.
It generally takes at least two days for results to be returned, making it difficult to use PCR testing for widespread surveillance.
Meanwhile, rapid tests look for antigens or proteins found on the surface of the coronavirus.
This screening method is faster, with results coming back within 15 minutes, but less accurate, as patients are more likely to have false negatives — getting a negative result even though they are 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.]
For the new study, published in JAMA Network Open, the team compared PCR tests with Direct Antigen Rapid Tests (DART) made by Cambridge, Massachusetts-based biotech company E25Bio.
Researchers had 257 individuals do a self-swab at home using DART twice a week for six months and then compared the results with those of PCR tests.
In total, DART was able to detect 15 of the 15 cases.
When used within three days of symptom onset, DART correctly identified 26 out of 27 samples for a sensitivity rate of 96.3 percent.
“Day three detection is almost as effective as day one detection in reducing the incidence of COVID-19, when 75 percent of a population is monitored,” the authors wrote.
In addition, for one participant, DART detected a COVID-19 infection one day before the PCR test.
“By conducting DART tests twice a week, the activities of the coworking sites were able to continue safely during the pandemic,” the researchers continued.
Most positive participants reported that they did not recognize the symptoms of COVID-19 until they received a positive result.
Regular home testing with DART allows infected individuals to be immediately identified and quarantined. Such surveillance can prevent viral transmission in personal work environments or other social settings.”