A man wore a sign to find his wife a kidney donor

Brooklyn, New York (CNN)It was a Friday afternoon like any other. I ate lunch, dropped off my dry cleaning, then stopped by my local Target to pick up some prescriptions.

But on the way to the counter I noticed a man in a black coat, wearing a backpack bearing a sign: "In need of a kidney for my wife, B+. 917-442-6202."

Unsure what to say, I quickly snapped a photo. And then he was gone. Although I generally hate posting pictures of people online without getting their approval,

I decided to share the image on Twitter since his face wasn't in it -- and because the message was so important.

Within a few hours, my picture of this man -- whom I've since identified as Raymond Thompson -- had gone viral. Celebrities such as Zach Braff, Martina Navratilova and Evan Rachel Wood shared it.

Actress Sarah Hyland, who recently revealed she had a second kidney transplant, shared the image, too.

Nearly a week later, the photo was past 23,000 retweets and 35,000 likes.

Thompson, who lives in Brooklyn with his wife Mylen and their 4-year old daughter, Rachel, doesn't even have a Twitter account.

But he knew something was going on when his phone began lighting up with calls and texts from unfamiliar numbers all over the world. Strangers were offering to give Mylen a kidney.

When I called Raymond, he recognized my name because others had sent him screenshots of my tweet.

Mylen met her future husband in an AOL chat room in 2000 and they bonded over their love of pro wrestling. She was diagnosed with kidney disease two years ago.

"She called me at work and said, 'Babe, you need to come home right now.' She said, 'I can't feel my right side. It's numb,' " Raymond told me. Now "she goes to a [dialysis] center for three hours, three days a week.

There's a machine that filters your blood. It takes a lot out of you."

Mylen and Raymond's family members got tested, but none were a match. Raymond was inspired by the story of Rob Leibowitz, who wore an "In need of kidney" T-shirt around Disney World -- a gambit that eventually worked.

One thing Raymond wants to clear up is that his family won't be setting up a GoFundMe for medical expenses -- between his work's insurance and Medicare, they're covered. It's just the kidney they need.

"I had a few people walk up to me and try to give me money," he said. "I refuse that every single time."

The Thompsons recently decided to switch Mylen's care to NYU Langone Hospital, a move that could open the door to test the many people who have called -- some from as far away as Pakistan and Australia -- to see if they're a match.

One of those people was Becca Joyner, who saw the tweet when it was shared by actress Patti Murin, who plays Anna in Broadway's "Frozen."

Joyner, a county clerk who lives in Farmville, North Carolina, suffers from Crohn's disease and recently underwent surgery to remove part of her intestine.

"I have been in and out of the hospital more times than I can count on my hand," she said. "I was terrified. Afterward I spent a week in the hospital, so I know what it's like.

Something was just telling me to reach out and see if you can help in any way."

Raymond plans to contact those who've reached out starting in January.

But even if a viral Twitter picture results in Mylen getting a kidney and moving off of dialysis, the Thompsons don't believe their work will be done.

"Sickness doesn't care who you are," said Raymond. "I appreciate everyone who reaches out. It means a lot to us to get the message out there.

"Sign up to be organ donors. There are so many people that actually need organs, especially kidneys. You have two and can live a healthy life with just one. Just sign up."

Indeed, the wait can be long for those in need of a kidney transplant. Of the nearly 100,000 people waiting for a kidney last year, only about 20% were able to find a match, according to the United Network of Organ Sharing.

Finding that match took an average of three to five years.

One person Raymond's message affected was me. Since our initial almost-encounter at Target, I've signed up to be a bone marrow donor and made an appointment to give blood.

And, since we both shop at the same Target, it's not surprising to learn that we're also neighbors. We have plans to get coffee after the holidays.

Correction: A previous version of this story misidentified the type of insurance the Thompsons have.