A teen saw the back of a man’s shirt at Costco. She pulled out her phone—and helped save his life.

Back in 2018, Karen Aguayo, a teenager out shopping with friends at a Costco, noticed something unusual on the back of a stranger’s T-shirt. The moment she read it, she stopped in her tracks.

The shirt read: “Kidney donor needed, Type B+, Ask me how.”

Karen didn’t hesitate. She approached the man, Robert Duran, and asked about the message.

"I felt like it was the right thing to do," she said. "Once I read his shirt, I felt something in my heart. It's not every day that you see shirts that say that and that was a first for my friends and me."

Elderly couple shoppingCanva

When she spoke with Duran, she learned that he and his wife had been wearing the shirts every time they left the house, hoping someone might see them and be moved to help.

"We go all over the place wearing them. We are just hoping someone sees them," Duran’s wife told AZ Central.

Duran was living with stage five kidney disease and undergoing dialysis three times a week, four hours at a time. He was on the national kidney transplant list, but the odds weren’t good. According to Organ Donor statistics, nearly 90,000 people are waiting for a kidney transplant in the U.S., and 13 die every day waiting for a match.

Costco at nightCanva

Duran and his wife were doing everything they could to spread the word.

"He said he has gone to the airport and pretends like he has a flight while wearing that shirt. That hit home," Aguayo said.

Karen knew she had to do something. She decided to post about Duran on social media, thinking someone online might be a match or could help by sharing the message.

In a now-deleted tweet, she wrote about meeting Duran and his search for a donor. It was later reposted by @Coach_Kap_29, who added: “We came across this man at Costco and we asked him about his shirt. He said he has been looking for a donor for four years and still nothing. Please do me a favor and RT this.”

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That tweet took off. It was retweeted more than 240,000 times.

Soon, people were reaching out from across the country to see if they were a match. The power of a single post snowballed into something incredible.

"I think of them as a saint. I think the Lord brought them down for me," Duran said.

In November 2019, Duran finally received a kidney and underwent a successful transplant, according to Fox10 Phoenix.

What started as a quiet walk through Costco turned into a life-saving moment—all because one teenager paid attention to the words on a stranger’s shirt and decided to act.

This article originally appeared earlier this year.