Five hospital patients were discharged without being tested for coronavirus to a Skye care home where there was later an outbreak.
NHS Highland sent the patients to Home Farm Care Home in Portree in late March - before routine testing for the virus was introduced.
Ten residents of the care home are known to have died in the outbreak.
NHS Highland said testing was carried out in line with national guidance but it could not comment on specific cases.
The Scottish Labour MSP for the Highlands and Islands, Rhoda Grant, made the discharges public.
She said she was told by NHS Highland bosses that the transfer of patients happened shortly after the Portree care home had sanctions lifted for care failures which had prevented new admissions.
Ms Grant was told the transfer happened after a risk assessment which found the care home's staffing levels had improved to an adequate standard.
She said NHS Highland bosses said they were satisfied that the problem had been significantly addressed so transfers took place for five people to Home Farm. But they said that as soon as there was a suspected case of Covid-19 at the home, the suspension of transfers was reinstated and that remains in place.
Ms Grant was also told the transfers took place in March and an updated policy on testing transfers only came out in late April.
A spokesman for NHS Highland said the health board advised "precautionary isolation" for two weeks for any patient discharged to a care home from a hospital.
He added: "As soon as Covid-19 is identified in a care home setting the home is immediately closed to new admissions.
"The last admission to Home Farm was in late March. The home confirmed Covid-19 at the end of April and an outbreak was declared at the beginning of May.
"While we can't comment on individual cases with respect to testing, we would test in accordance with national guidance for the management of suspected respiratory outbreaks in care homes and any patients, residents or staff with suspected Covid-19 in an NHS Highland hospital or care home are cared for under our Covid-19 infection control procedures."
'Informed by the scientific advice available at the time'
The Scottish government said it also could not cannot comment on individual cases.
However, it said all decisions on the Covid-19 response were informed by the scientific advice available at the time and that it would continue to be tailored as more was learned about the virus.
A spokeswoman added: "Scottish government guidance is clear that anyone discharged from a hospital to a care home should be self-isolating for 14 days. The guidance to care homes is also very clear about isolation and social distancing being the most important factors in managing and preventing infections in care homes."
She added that there had been a "dramatic increase" in PPE supplies since the start of the pandemic.
Ms Grant said: "I am concerned that a care home that had previously been closed to new admissions had this status changed in the face of the Covid-19 pandemic.
"At a time when more checks and balances should have been put in place to protect vulnerable people it would appear these had been reduced and people were discharged - untested - to this care home."