Minnesota Attorney General Lori Swanson has accused Allina Hospitals and Clinics of charging patients unlawfully high interest rates on unpaid medical bills and filed a lawsuit that could affect the bills of thousands of consumers. Allina charged patients interest rates as high as 18% on medical debt, even though, Swanson asserted, Minnesota law caps rates on such debt at 8%. Swanson said she wants Allina to reduce interest rates charged by its MedCredit Financial Services unit and make refunds to patients who were charged high rates in the past. She is also pursuing civil penalties of up to $25,000 per violation.