SARS-CoV-2 tests that give results in 15 minutes scored well on sensitivity, according to a study by Unisanté in Lausanne, Switzerland.
The tests, which involve taking a sample of nasal secretions from the back of the nose and throat, test for a protein present in the virus. The main PCR test used currently looks for genetic material specific to the virus, a more complicated laboratory-based process that can take around a day.
The Unisanté study, done in conjunction with the Institute of Microbiology at the CHUV hospital and Vidy Med, involved testing 380 people with possible Covid-19 symptoms with both the rapid test and the PCR test. 26% tested positive on the PCR test and 22% with the rapid test. Essentially, 85% of those testing positive on the PCR test tested positive on the rapid test. The 85% rose to 94% among those considered the most contagious.
The rapid test proved most effective on those with a high viral load, a group that is typically more infectious.
A rapid test that identifies the most infectious could be helpful for cutting transmission, even if it doesn’t pick up as many cases as the slower PCR test.
In addition, the speed of the test means contact tracing and isolation can get underway sooner, which also helps to cut disease transmission.