"I have no idea," said Andy Dillard, 30, of Ecru. "I knew at the hospital."
"I'm AB positive, so I think you had to be A or B," said Michael Downing, a 31-year-old Guntown resident.
"Man, I don't know," Dillard said.
It doesn't matter. The main thing is a battery of tests determined that Dillard was a match for his friend and co-worker at CSA in Tupelo.
"I wasn't going to waste my time or waste their time - 'Oh, this guy's a match,' - then not do it," Dillard said.
The pair met at Itawamba Community College, where they played on the baseball team together. Dillard knew Downing had health issues, but nothing more specific than that.
Downing had known since eighth grade that he'd need a transplant someday. He had IgA nephropathy. An excess of protein ate away at his kidneys.
"It killed my kidneys before my doctors were expecting," Downing said. "They thought I would be 50 or 60 years old before I needed a transplant. It got more aggressive."
On Feb. 25, he learned time had run out, and he started filling out paperwork to send to different transplant hospitals. Word got back to Dillard from a mutual friend.
"Downing's not the kind of guy who goes out and says, 'Hey, I need a kidney,'" Dillard said.
Dillard didn't know anything about the process, so he did some research.
"I saw the life expectancy for someone who donates a kidney is higher than for the general population," he said.
On the downside, donors can't compete in Ultimate Fighting Championship matches.
"There went that career choice," Dillard said.
In addition to their ICC days and working together, the pair have another connection.
Dillard and his wife, Stacy, had a new baby girl, Makynlee, this year. In the middle of Downing's health issues, he and his wife, Le, were expecting their son, Ben.
The young Downing was set to arrive at about the time of his father's surgery, but he was three weeks premature.
The two men will have a connection that's more intimate than most, as their lives go forward.
"I feel like a new person. I have energy again," Downing said. "There at the end, I could barely walk."
"It's a whole lot easier to know your kidney is with someone who's going to take care of it," Dillard said. "Being friends and knowing what kind of guy he is ... The way it came out is definitely God's plan."