Polyvinylpyrrolidone induced artefactual prolongation of activated partial thromboplastin times in intravenous drug users with renal failure.

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, followed by a summary of findings in 11 other patients and results of an in vitro experiment where plasma was spiked with PVP at increasing concentrations. APTTs measured with STA PTT automate (Stago) were prolonged in all patients as well as in spiked samples, while supplemental coagulation parameters and APTTs measured with HemosIL Synthasil (IL) or Actin FSL (Siemens) were within reference intervals. These results indicate that APTT-interference from 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 history of intravenous drug abuse. This article is protected by copyright. All rights reserved.