Mixed nucleic acid testing is nucleic acid testing when multiple people nucleic acid collection samples are mixed to achieve the effect of testing multiple people at once, which can effectively improve the efficiency of staff testing. There are two types of mixed nucleic acid testing, one is the sample mix, the other is a mixed swab. Mixed test is usually “5 mixed 1” and “10 mixed 1”, that is, the samples of 5 or 10 people into a collection tube, with a test reagent detection, more suitable for large-scale population as quickly as possible to screen out infected people. 1, sample Mixing: Using the pharyngeal swab sampling method, the swab head is dipped into a tube containing 1-3 ml of virus preservation solution for each collection. In the mixing room, 200ul of each of several samples collected (in principle, no more than 5) will be taken and mixed thoroughly to form a mixed sample to be tested, and then nucleic acid detection will be performed. If the mixed sample detects Ct value (an objective indicator to judge negative or positive nucleic acid test), all individual samples need to be resampled and single person single sample nucleic acid test will be performed as usual; 2. Mixed swab: put samples from 10 people into one collection tube and test with one test reagent. If the test result is positive, it is necessary to quarantine these 10 collected persons as a single person and perform single-sample nucleic acid testing on each person. If the test results are all negative again, the 10 persons can be released from quarantine, but if there are positive persons, they need to be reported in a timely manner. Mixed sample testing is only applicable to the first round of full nucleic acid testing conducted in certain low-risk areas, and its results cannot be used as a basis for final confirmation of diagnosis. It is not recommended for key regional populations, such as neighborhoods with recent outbreaks, containing confirmed cases and asymptomatic infected persons, older neighborhoods, densely populated neighborhoods, mobile population clusters and populations recently out of the province, and patients attending medical institutions.