A new test for COVID-19 combines the speed of over-the-counter antigen tests with the accuracy of PCR tests that are processed in medical labs and hospitals. The Harmony COVID-19 detects genetic material from the SARS-CoV-2 virus, but whereas conventional PCR tests can take several hours, the Harmony kit provide results in less than 20 minutes for some samples and with similar accuracy.
The researchers developed Harmony to be simple and easy-to-use, employing ready-to-use reagents. The test uses a PCR-like method to detect the presence of the SARS-CoV-2 RNA genome in a nasal swab sample with the aid of a small, low-cost detector. A smartphone is used to operate the detector and read the results. The detector can handle up to four samples at a time and would fit into a standard car’s glove compartment.
Initial results show that the Harmony kit is 97 percent accurate for nasal swabs. The Harmony kit detects three different regions of the virus’ genome. If a new variant has many mutations in one region, the new test can still detect the other two. It can, for example, detect the omicron variant, which has dozens of mutations in the region of the genome that encodes the so-called spike protein.
Although tests based on PCR are highly accurate, a key limitation is that PCR tests require dozens of cycles of heating and cooling to detect genetic material in a sample. The new test this issue by relying on a PCR-like method known as RT-LAMP, which doesn’t have the same stringent temperature-cycling requirements.