The auction of a vial of blood purportedly taken from Ronald Reagan after an assassination attempt in 1981 has appalled the former U.S. president's foundation.

PFC Auctions, a company based in Guernsey in the United Kingdom, announced Sunday it would sell the vial of blood in an online auction scheduled to end on Thursday, Reuters and other media reported.

The sample was taken at George Washington University Hospital on March 30, 1981, after Reagan was wounded by John Hinckley Jr. in Washington, D.C., the auction company said on its website. The company said the vial came from a person whose late mother had worked at a medical lab.

"If indeed this story is true, it's a craven act and we will use every legal means to stop its sale or purchase," John Heubusch, executive director of the Ronald Reagan Presidential Foundation, said in a statement cited by Reuters.

Reagan suffered a punctured lung and internal bleeding in the shooting outside the Washington Hilton Hotel. Hinckley was found not guilty by reason of insanity.

'I said, "Am I in any kind of trouble or will there be some black cars/SUVs or helicopters hovering above my home?"' —Unidentified seller

At the auction site, notes describing the provenance of the blood quoted the seller as saying they had contacted the Reagan National Library to see if the library was interested in purchasing it.

As well, the seller says Reagan would have approved of the auction.

The unidentified seller describes the call-back from an official at the Reagan National Library.

"Prior to hanging up the phone, he said to me, 'Do me a favour, don’t move from where you are, I will call you back within 30 minutes, but I have to make a couple of phone calls to seek legal counsel, consult with National Archives, the FBI and other three or four letter agencies that I have heard of,'" the seller's note says.

"I said, 'Am I in any kind of trouble or will there be some black cars/SUVs or helicopters hovering above my home? And he said not yet, but possibly in the very near future depending on what he learned from the phone calls he had to make. I told him, "'All right, I will not move from where I was sitting and would await his return call.'"

In the end, the note says, there was no official interest in buying the vial.

So the seller decided not to donate it, but rather put it up for sale.

"I had served under President Reagan when he was my commander-in-chief when I was in the army from ’87-’91,  and … I was a real fan of Reaganomics and felt that President Reagan himself would rather see me sell it rather than donating it."

Reagan was president from 1981 to 1989. He was diagnosed with Alzheimer's disease in 1994. He died in 2004 at age 93.