Relevant information shows that the nucleic acid results of all employees in Zhoukou City 18 came out at 8: 00 pm on 19, because all employees in Zhoukou City need to submit the test at 8: 00 pm on the day when the test ends, and it takes 24 hours to query the results, so the nucleic acid results of all employees in Zhoukou City 18 came out at 8: 00 pm.