The new option was announced Tuesday by Facebook CEO Mark Zuckerberg as a way to boost the number of potential organ donors.
By the end of the day, 6,000 people had enrolled through 22 state registries, according to Donate Life America, which promotes donations and is working with Facebook. On a normal day, those states together see less than 400 sign up.
The new feature is not yet available to Canadian users, but Ontario's organ and tissue donation agency says there was a spike in registrations on Tuesday due to the media coverage of the launch.
"There were 363 online registrations yesterday through www.BeADonor.ca, while on an average day we would expect to see about 50," said Ronnie Gavsie, President and CEO of Trillium Gift of Life Network.
"We’re very happy that Facebook has chosen to highlight the importance of organ and tissue donation," he said.
In the U.S., the response "dwarfs any past organ donation initiative," said David Fleming, chief executive of Donate Life America, in a statement.
The Facebook feature allows users to share their decision to be an organ donor on the website. More than 100,000 did that by Tuesday night, according to Facebook, which is working with Fleming's group to encourage Facebook users to also officially register as donors with their state.
A link on the site connects to online donor registries. At least 22,000 people had followed that link as of Wednesday afternoon. Information from 22 states indicates that a third or more of them filled out the form to register, said Donate Life America spokeswoman Aisha Michel.
California — where Facebook is headquartered — reported startling results. About 70 people register online as organ donors each day. But in the 24 hours after Zuckerberg's announcement, about 3,900 signed up.
"We're just thankful we have this opportunity to bring more people into the process," said Bryan Stewart, a spokesman for OneLegacy, which co-ordinates transplants in the Los Angeles area.
"We're looking forward to seeing how long this activity lasts, and at what level," he added.
Facebook, a social network site founded in 2004, has 526 million daily users around the world. It was Facebook's idea to add the option, after Zuckerberg took a personal interest in the issue, Michel said. The feature is available in the U.S. and the United Kingdom.
As with some personal information on Facebook, organ donor status can be kept private or shared publicly or only with friends.
More than 114,000 Americans are currently on waiting lists for transplants of kidneys, livers, hearts and other organs, according to United Network for Organ Sharing (UNOS), the organization that runs the nation's transplant system. More than 6,600 died last year waiting for an organ.
According to UNOS, 43 per cent of adults in the U.S. are registered as donors. Organs can only be used though under certain circumstances, such as when someone dies from a major head injury and a ventilator can keep the organs viable. Less than 1 per cent of U.S. deaths annually are under such circumstances. And sometimes the opportunity is lost because family members didn't know about the person's wishes on organ donation.
The Facebook feature "is a unique opportunity for people to make their decision known," UNOS Executive Director Walter Graham, said on a statement.
Most people register as organ donors when they get a driver's licenses, but about 2 per cent sign up through online registries. Both represent legal consent for adults. For children who want to be donors, parental consent is still required.
Donate Life America: http://donatelife.net/
Facebook directions: http://tinyurl.com/794o4d9