Although re-infection and aggravation of clinical symptoms have not been found in retest virus nucleic acid positive patients with coronavirus disease 2019（COVID-19）

the potential risks cannot be ruled out. Therefore

this article was designed to analyze the situation of retest virus nucleic acid positive COVID-19 patients

and to summarize the potential reasons. As a result

virus residual

false-negative result of previous test

weakened individual′s immune function

virus recurrence or re-infection

drug abuse

and immunosuppression were the reasons that may lead to retest positive results. Accordingly

three principles to prevent retest positive in convalescent COVID-19 patients were put forward

which included "to remove the virus thoroughly"

"to strengthen the vital qi"

and "to improve the constitution".