Users of antigen test kits should try and use them at times when diagnoses are likely to be most useful, a Public Health Ministry specialist suggested yesterday.
Kamthorn Malatham, chairman of the Infectious Disease Association of Thailand, said the antigen test, which detects protein chains, is of particular value when taken two days before symptoms show and in the week following the first signs of the virus.
Dr Kamthorn said the antigen test can also produce a false negative if there are low virus loads.
However, any early diagnosis can reduce the severity of symptoms by ensuring people get timely treatment, as well as helping stop them from spreading the disease unwittingly.
He also urged those with known exposure but no symptoms to bear in mind that the tests can still produce false results, and act in a hygienic and conscientious manner.
He said antigen test results are less accurate when used by those with no symptoms.
"The antigen test is at its most useful when given to those who have been exposed to Covid-19 and have begun to show symptoms," he said.