P was diagnosed with bacterial endocarditis, and as part of her treatment, she was administered and prescribed the antibiotic Gentamicin. P was eventually diagnosed with Gentamicin vestibular ototoxicity, an illness solely caused by taking the antibiotic. D personnel told P that she might never completely recover from the illness. P was discharged from Mayo on July 24, 1996. She returned on September 5, 1996, and September 13, 1996, for follow-up examinations. P filed her complaint on May 29, 1998, wherein she alleged medical malpractice. On June 1, 1998, P attempted to serve D by mailing a copy of the summons and complaint and enclosing an Acknowledgment of Service form for D to return. D received the materials two days later but did not sign and return the acknowledgment form. On June 15, 1998, P's counsel contacted D's in-house counsel, who informed him that D would not admit service or assist P in any way in suing his client. On June 22, 1998, P filed an amended complaint, which she again mailed to D with an Acknowledgment of Service form. D did not return the form, and on September 3, 1998, P's counsel again contacted D's counsel, who again told him that D would not execute the form. On September 4, 1998, P mailed copies of the amended summons and complaint to the Olmstead County Sheriff's Department. The Sheriff's Department received the materials on September 8, 1998, and served Mayo the following day. D moved for summary judgment on the ground that Larsen's claim was time-barred. The district court granted the motion, noting that the statute of limitations for medical malpractice claims in Minnesota was two years. The court held that this case falls into the 'single act' exception because: (1) the alleged malpractice terminated on July 13, 1996, when P was administered and prescribed Gentamicin; (2) the malpractice became irrevocable on July 19, 1996, when P was diagnosed with vestibular ototoxicity; and (3) P was fully aware by July 23, 1996 of the facts upon which her claim is based. Since service was not effective until September 8, 1998, the date the Olmstead County Sheriff's Department received the summons and complaint for service on D, and thus P's claims were time-barred. P appealed.