title: Polyvinylpyrrolidone induced artefactual prolongation of activated partial thromboplastin times in intravenous drug users with renal failure.
abstract: Essentials Prolonged activated partial thromboplastin times (APTT) were found in drug users with renal failure. An oral methadone solution containing polyvinylpyrrolidone (PVP) had been injected intravenously. Spiking normal plasma with increasing concentrations of PVP resulted in artifically prolonged APTT. APTT prolongation may indicate PVP deposits as underlying cause in patients with renal failure.
  
  
  CONCLUSIONS
  Unexpectedly prolonged activated partial thromboplastin times (APTTs) were noted in several patients with chronic renal insufficiency and a history of intravenous drug abuse. Deposits of polyvinylpyrrolidone (PVP), an excipient in one oral methadone solution used in opioid maintenance programs, were found in renal biopsies. One case is described in detail, and this is followed by a summary of findings in 11 other patients and the results of an in vitro experiment in which plasma was spiked with PVP at increasing concentrations. APTTs measured with STA PTT automate (Stago) were prolonged in all patients and in spiked samples, whereas supplemental coagulation parameters and APTTs measured with HemosIL SynthAsil or Actin FSL (Siemens) were within reference intervals. These results indicate that interference with APTTs by PVP is reagent-dependent. We suggest that a prolonged APTT should raise the suspicion of PVP deposit-associated kidney disease in patients with chronic renal failure and a history of intravenous drug abuse.
authors.affiliation: Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway.|Norwegian Quality Improvement of Primary Health Care Laboratories (Noklus), Haraldsplass Deaconess Hospital, Bergen, Norway.
authors.forename: A H
authors.initials: AH
authors.lastname: Kristoffersen
authors.affiliation: Laboratory of Clinical Biochemistry, Section of Clinical Pharmacology, Haukeland University Hospital, Bergen, Norway.
authors.forename: T K
authors.initials: TK
authors.lastname: Bjånes
authors.affiliation: Department of Medicine, Haukeland University Hospital, Bergen, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Jordal
authors.affiliation: Department of Pathology, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Leh
authors.affiliation: Department of Pathology, Haukeland University Hospital, Bergen, Norway.
authors.forename: F
authors.initials: F
authors.lastname: Leh
authors.affiliation: Department of Medicine, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Svarstad
keywords: activated partial thromboplastin time; blood coagulation; drug users; factor VIII; povidone; renal insufficiency