ST. AUGUSTINE, Fla. -- Human error that caused a man to die after receiving the wrong blood during a transfusion at a Florida hospital has one family considering taking legal action.

Blake Oliver died unexpectedly one week before his 68th birthday.

"He came from New Mexico to visit for the Christmas holiday and didn't get to leave," said Oliver's sister, Patti Canakaris. "I'm the last person left in my family. Everybody else is gone but me, and that's a pretty lonely place to be."

Canakaris, of St. Augustine, said she is holding onto the memories of her only brother.

She told Channel 4 that Oliver was admitted into the Bert Fish Medical Center in New Smyrna Beach, Fla. because of sharp stomach pains.

Canakaris said a few days later he went into surgery and died. However, his death was not from the surgery, but because of a hospital-admitted mistake, according to Canakaris.

"It was just the most awful, ridiculous scenario, in that it could have been 100 percent prevented if people had just followed the rules that were already in place," Canakaris said.

She said the hospital told her that an employee accidentally tested Oliver's roommate for his blood type and then used the mismatched blood in Oliver's surgery.

"Blake's blood type is O positive. The roommate's blood was A positive. The roommate's blood being A positive was labeled Blake Oliver and given to him transfused," said Canakaris.

She said she was in shock when the hospital broke the news.

"In a way, I felt sorry for them to have to sit across the table and tell a family that they had in essence killed your family," Canakaris said.

Hospital spokesman Garry Mac said they are also devastated and determined to prevent such grave mistakes in the future.

"We immediately did a review of policy and procedures and even went so far as to added yet another layer of checks and balances over the policies and procedures involved," Mac said.

In the meantime, Oliver's family said it is taking it one day at a time and considering legal actions against the hospital.

"I just want to make sure that another family doesn't have to deal with something like this because it's just unconscionable," Canakaris said.

The Bert Fish Medical Center said it has turned over its information to a state agency for investigation. Pending the outcome of the investigation, one of the hospital employees could face termination.