Officially, Tammy Miller is a security guard at the DaVita Cobbs Creek Dialysis center.

Unofficially, she is a one-woman welcome wagon.

She greets patients at their cars with a smile and song. She dances alongside them as they enter the facility. She helps settle them in their stations — setting the TV to their preferred channel, grabbing a blanket, fetching a drink or snack, offering words of comfort and support — and providing enough warmth to heat the building on 60th Street in Southwest Philadelphia.

“She’s our ray of sunshine,” said Simone Iovacchini, the center’s facility manager. “She just radiates positive energy.”

The twist in this story is that it’s usually Miller who provides the pep to the folks who pull up in cars outside the facility. But on Friday, it was the cars — with their signs and decorations, with smiling folks inside leaning hard and happy on the horns — who turned the good vibrations back her way.

That’s when DaVita and the Borough of Yeadon teamed up for Drive by Wave for Miller, a car parade and balloon-festooned celebration to honor Miller for her cheerful, infectiously upbeat service.

“I was completely off guard,” Miller said. “It was overwhelming. It made me feel like what I’m doing really matters.”

Miller was feted by a car parade that featured Yeadon fire and police vehicles. She was honored by proclamations by Yeadon Mayor Rohan Hepkins, State Rep. Joanna McClinton, and State Sen. Anthony Williams.

“Tammy brightens every day,” said Jenna Honig, a nurse at the facility. “This can be really hard on the patients. They have to come in three times a week, sit in a chair for four hours, not moving. They’re scared.

“She knows all their names. She knows their life stories. She is so gentle and kind with all of them.”

Miller, 53, said she has always been a positive person, looking for the bright side of every situation.

“Happy-go-lucky, that’s always been me,” Miller said.

She said she has felt additional compassion for dialysis patients since she used to help her stepson, Arthur Grandy Jr., through similar treatments. She said he died of complications from kidney failure in November at the age of 38.

She tries to provide even more reassurance for patients in his memory.

“I know what they are going through because I went through it with him,” Miller said. “I want to help people. But I do it even more because I remember what it was like with my stepson and I want to remember him.”

Miller said she used to dance with Grandy Jr., usually to the sound of the Temptations and the Chi-Lites. She tries to bring that same, soulful style to her singing and dancing with dialysis patients.

“Oldies but goodies, that’s me,” she said.

Miller was born and raised in West Philadelphia. She graduated from University City High. She has been a security guard since 1998, when she first applied for a position at SpectaGuard, which later became Allied Security. She now works for GardaWorld of Philadelphia Security Services.

“I wanted to take it home and the woman said, ‘Fill it out now,’” Miller said of the application. “They hired me on the spot.

“I love being a security guard. I love people, interacting with them, getting to know them. They see me coming, see me dancing, and they know, ‘No stress here.’”

She usually takes two shifts a week at DaVita Cobbs Creek Dialysis, reporting to work at 4:30 a.m.

“I’m not a morning person, so that’s my challenge, the 4:30 challenge,” said Miller, who lives in the West Oak Lane section of the city.

She works two more shifts at Penn Medicine. She usually picks up another fill-in shift per week at either Cobbs Creek or Jefferson Health.

She is also an EMT, having volunteered with the Bensalem Fire Rescue company.

“To me, it’s all about customer service,” Miller said. “People are scared, they are nervous. I’m here to tell them, “It’s going to be all right. It’s going to be OK.’”