Ellen Siebern has made a career out of working for free.
The 88 year old started volunteering at Rady Children's Hospital 25 years ago, and has since put in more than 5500 hours helping nurses with their daily tasks.
"Their job is to take care of the children, and our job is to make things as easy as we can for them," she said.
Siebern does not usually go room to room visiting sick kids. Her tasks are more tedius, but no less important. She counts medical supplies, delivers blood, and does it with a smile.
"She radiates, and she's just happy," said nurse Kimberly Faimon.
"She smiles all the time," echoed Hemotologoy Oncology director Dolores Esparza. "It's very contagious. You can't help but smile, if she's smiling."
While Siebern's trademark around the hospital hallways seems to be happiness, the job started out in darker times for her. Sibern had lost her husband of more than 30 years.
"Very selfishly I guess I was trying to get over the loss of my husband," she said. And that's not the only reason this job is personal to her.
Siebern's oldest granddaughter was diagnosed with a brain tumor when she was 18 months old, and was treated at Rady Children's Hospital.
"When she grew up, she was validictorian of her high school and went on to Berkeley," said the proud grandmother.
That experience gave Siebern a first hand look into this hospital.
"The nurses are so great," she said. "They care so much about each child."
And over the past 25 years, she's gained an appreciation for the patients as well, even at arm's length.
"I don't have to interract with them. I just enjoy seeing little kids. They are so fun to watch, and they are so tough, they really are."
April is National Volunteer Appreciation Month. Ellen Siebern technically works for free, but like so many other volunteers, would tell you she's paid in other ways.
"I think most of the time, when you talk to a volunteer, they don't consider it work. It's something they enjoy. And I enjoy this," she said.