The care home in suburban Des Moines, Iowa, has been fined £8,185.
The Iowa Department of Inspection and Appeals said in a report filed on Wednesday that the 66-year-old woman was declared dead at the Glen Oaks Alzheimer's Special Care Centre in Urbandale on January 3.
The woman, whose name has not been released, had early onset dementia, anxiety and depression and had been in hospice care since December 28.
She was placed in a zipped body bag and taken to the Ankeny Funeral Home and Crematory, where workers found that she was breathing and called 911, the report said.
She was taken to Mercy West Lakes Hospital, where she was breathing but unresponsive.
The woman was ultimately returned to hospice care, where she died on January 5 with her family by her side, according to the report.
A Glen Oaks staff member who had worked a 12-hour shift and was on the team caring for the woman told investigators she first reported to a nurse practitioner early on January 3 that the woman was not breathing and had no pulse.
The nurse practitioner who had cared for the woman throughout the night also was unable to find a pulse and said the woman was not breathing.
She continued to assess the woman for about five minutes before determining the woman had died.
The woman was declared dead about 6.30am local time, roughly 90 minutes after the staff member's first report.
A funeral home employee and a second nurse practitioner who put the woman into the body bag and the funeral home's vehicle about an hour later also found no signs of life, according to the report.
The department of inspections and appeals found the care centre "failed to provide adequate direction to ensure appropriate cares and services were provided" before the woman was declared dead.
Lisa Eastman, executive director of the Glen Oaks Alzheimer's Special Care Centre, said in a statement that the centre cares deeply about its residents and remains committed to supporting end-of-life care.
"All of our employees are given regular training in how best to support end-of-life care and the death transition for our residents," Ms Eastman said.
The Ankeny police department is not pursuing criminal charges, spokesperson sergeant Corey Schneden told The Des Moines Register.
The Iowa Capital Dispatch reported in February 2022 that Glen Oaks had been fined 500 dollars (£409) for failing to perform the required background checks on employees.
It found five workers had not received the required training to work in a memory-care facility.