On Friday, the National Health Commission of China released a notice that showed the State Council deciding to add rapid antigen testing (RAT) as a supplement to nucleic acid testing (NAT), a method that has been used since the outbreak began. Stock prices of RAT kit makers listed on the A-share market, such as Wondfo and Orient Gene, have risen sharply.
In principle, the RAT method detects protein antigens on the surface of virus particles in human samples while the NAT method only detects remnants of the virus in human samples. The former needs about 15 minutes, which is one tenth of that of the latter. Moreover, RAT does not rely on equipment, laboratory and human transportation, but only needs a single test paper.
The main difference between RAT and NAT lies in infection time. RAT can detect a positive case 3-7 days after infection, while the nucleic acid detection needs 2-14 days.
According to the Health Commission, there are three kinds of people suitable for RAT, namely, those who go to primary medical institutions with respiratory virus infections and other symptoms within five days, those in quarantine and residents within communities who need to undergo self-testing.
Moreover, when primary medical and health institutions receive people with respiratory virus infections, fever and other symptoms within five days, if they can administer a nucleic acid test, they should still choose that method first. Other institutions that do not have the ability of using the NAT method can choose the faster method – RAT.
According to the notice, if community residents need to self-test, they can purchase RAT kits through retail pharmacies, online platforms and other channels.
The notice issued by the Health Commission still recognizes the importance of nucleic acid detection, saying that patients who are confirmed to be positive by an antigen test need to be reconfirmed by a nucleic acid test immediately. The Chinese mainland on Thursday reported 397 locally transmitted COVID-19 cases, showing the country’s urgent need for a quicker testing method.