Jakarta, CNBC Indonesia - There are many cases when a person's antigen test result is negative, even though the symptoms of Covid-19 are already visible.In a press conference some time ago, the Ministry of Health revealed that the test may not have detected the virus.This was conveyed by the Director General of Health Services Abdul Kadir.He said people infected with the Corona virus would not necessarily be detected with Covid-19 on the first and second days if the test was carried out with a rapid antigen test.For this reason, if people experience symptoms of Covid-19 and get negative results, they are asked to immediately carry out a PCR (polymerase chain reaction) test."Rapid antigen test is positive or negative, it is determined by the level of antibodies formed in the body. If we have high antibodies formed in the body, for example in early infections on the first day or the second day it may be negative, but with PCR it is already positive "explained Abdul Kadir.At that time, the spokesperson for the Covid-19 vaccination of the Ministry of Health, Siti Nadia Tarmizi, said that people would continue to quarantine if the results were negative.The self-isolation was carried out for five days, then retested.This is done because it is possible that someone has actually been infected with the virus but was not detected by the Covid-19 test kit."If the results are negative, they must be quarantined or there is an incubation period for this virus which may not have been tested positive. We quarantine for five days. On the fifth day, we will test again," said Siti Nadia.Siti Nadia also explained some of the symptoms of Covid-19, especially the Omicron variant.At mild levels, the patient will experience cough, runny nose, headache, and sore throat.