Repeat Covid-19 testing is no longer considered appropriate for people who have recovered from the illness, according to the HSE clinical lead on infection control, Professor Martin Cormican.
The microbiologist and disease expert said the thinking on retesting had changed because they were learning more about the virus.
"We have learned a lot in the last three or four months, and repeat testing is generally not appropriate in deciding that somebody is no longer infectious,” he said.
There might be very few exceptions, but the practice now was to count 14 days from the time symptoms started, or from the date a swab test was taken, with the person no longer considered infectious if fever-free over the final five days.
He was speaking during an online update on infection prevention and control in residential care facilities by the Health Protection Surveillance Centre.
Prof Cormican said retesting any time in the three months after infection rarely had any value.
Anybody admitted to a residential care facility is tested for the coronavirus, but Prof Cormican warned not everyone with the virus would be detected. While the test was still recommended, a thorough clinical assessment would pick up the vast majority of cases.
HSE national antimicrobial resistance and infection control team member, Mary McKenna, said it was recommended that testing should be performed within three days of planned admission to a residential care facility.
Where testing is not performed before admission, it should be carried out within one day of admission.
Prof Cormican said testing won't replace clinical assessment and, where the test has come back negative and a person has symptoms, the matter should be discussed with the patient’s doctor.