SACRAMENTO (CBS13) — You’ve heard of luggage and other personal items being left behind on a flight, but what about a human heart?

The flight took the organ on ice from a courier at Sacramento International Airport bound for Seattle where the heart’s valve tissue was set to be used. But like a mishandled bag, the heart was mistakenly kept on the connecting flight to Dallas instead of being taken out of the cargo hold.

“It’s very clearly labeled that this is a gift. It’s clearly labeled that this is human tissue for transplant so that the handlers are aware to treat this very carefully,” said Deanna Santana with Sierra Donor Services.

Santana said she has not seen anything like this in her seven years at Sierra Donor Services.

“Everybody involved is going to evaluate the process, they’re going to make sure what happened and make sure this doesn’t happen again,” Santana said.

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More than an hour into the connecting flight to Dallas, the pilot turned around, leading to a five-hour delay for passengers.

In a statement, Southwest Airlines said, “the shipment was delivered to its destination within the window of allotted time by our cargo customer. Nothing is more important to us than the safety of our customers and the safe delivery of the precious cargo we transport every day.”

Valve tissue has a 48-hour window of viability. Amazingly, the heart made it in time to save the life of its intended recipient.

Sierra Donor Services tells CBS13 it called the donor’s family to alert them of the delay. The company serves about a thousand families in our region every year.

They said the valve tissue donated has the potential of saving three lives.