There is no clear probability that the first negative test will be followed by a second positive test, and it is mainly related to whether the person being tested has been infected or not, history of exposure, vaccination, etc. There are no clear statistics on whether the test will go from negative to positive. There are no clear statistics on whether a person can go from negative to positive. Although this is the case in some people, it is usually due to their own factors such as viral infections and not due to the nucleic acid test itself, so if there are no such factors, then there is no need to worry about being positive as a result of the nucleic acid test. If the test is negative the first time it is performed, and there is a history of exposure or a definite infection before the second test is performed, the probability of the second test being positive is higher. The probability of a false-positive test is higher if you were not immunized with the new crown vaccine at the time of the first test and were immunized within 24 hours before the second test. Thus it is mainly related to self-factors and has little to do with the nucleic acid test itself.