Mer samstämmiga laboratorieresultat efter övergången till INR. Skillnaderna mellan sjukhus- och primärvårdslaboratorier utjämnade

Translated title of the contribution: Less variation in laboratory results after the introduction of INR.

Andreas Hillarp, Nils Egberg, Inger Fagerberg, Tomas L Lindahl, Gunnar Nordin, Lennart Stigendal

Research output: Contribution to journalArticlepeer-review

2 Citations (SciVal)


In 1999 a new and simplified procedure for calibration of the Owren prothrombin time (Owren PT) assay was introduced in Sweden by the national external quality assessment scheme (Equalis). The new protocol allowed local calibration by means of lyophilised national plasma calibrators and expression of results as an international normalised ratio (INR). A two-year follow-up involving analysis of data from all laboratories that have returned results to Equalis is reported. There was a significant reduction in both between-laboratory and within-laboratory variation after the introduction of the new calibration procedure. For the larger hospital laboratories analysing external controls with INR>2, the mean coefficient of variation (CV) was reduced from 9.1% to 5.6% (P<0.0001). The corresponding results from smaller laboratories in the primary
health care units showed a similar decrease in CV from 8.8% to 6.3% (P<0.0001). This study shows that the Owren PT assay is well suited for INR calibration employing calibrant plasmas.
Translated title of the contributionLess variation in laboratory results after the introduction of INR.
Original languageSwedish
Pages (from-to)5068-70, 5073
Issue number50
Publication statusPublished - 2002

Subject classification (UKÄ)

  • Medicinal Chemistry


  • Anticoagulants: blood
  • Anticoagulants: pharmacokinetics
  • Health Care
  • Sweden
  • Hospital: standards
  • Primary Health Care
  • Prothrombin Time
  • Quality Assurance
  • Anticoagulants: administration & dosage
  • Calibration: standards
  • Comparative Study
  • Confidence Intervals
  • English Abstract
  • Follow-Up Studies
  • Human
  • International Normalized Ratio: standards
  • Laboratories: standards
  • Laboratories


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