Twin Cities rapper P.O.S. is canceling his national tour because of health concerns. However, a concert next Friday at First Avenue in Minneapolis to celebrate the release of his latest album, "We Don't Even Live Here," will go on as scheduled.

In a video posted to YouTube, P.O.S. (aka Stef Alexander) said failing kidneys are to blame for the cancellation: "Both of my kidneys are garbage. They've been going bad since I was a teenager. It's a really inopportune timing, but, now's the time. I need a new kidney."

He said he's been on dialysis for about a month and planned to take a machine on the road, but complications will make that impossible.

Last month the condition forced him to cut short a gig at McNally Smith College of Music in St. Paul and go to the emergency room. He had just gotten out of surgery to install a catheter for home dialysis, "and it was too early [to perform]," he told the Star Tribune earlier this month.

"I had some kind of unidentified trauma when I was 13 or 14, something that triggered scarring in my kidneys. It could've been a bad fall, skateboarding or whatever."

He's asking fans for financial donations, and possible donor matches for a new kidney.