A comparison of artificially-depleted, lyophilized coumarin and fresh coumarin plasmas in thromboplastin calibration

L. Poller, A. M H P Van Den Besselaar, J. Jespersen, A. Tripodi, D. Houghton

Research output: Contribution to journalArticle

Abstract

Artificially-depleted lyophilized plasmas and lyophilized coumarin plasmas were prepared and compared with fresh coumarin plasmas to assess their comparative reliability in local thromboplastin calibration using the manual prothrombin time (PT) technique. Their certified PT values were inserted in turn on the vertical axis in place of the PT obtained with fresh coumarin plasmas. PT results were obtained at eight ECAA national laboratories ('test centres') and inserted on the horizontal axis. The resulting thromboplastin calibration slopes were compared with conventional fresh coumarin plasma calibration slopes at the same 'test centres'. When 60 artificially-depleted plasmas were substituted for 60 fresh plasmas, the mean calibration slopes with the human plain International Reference Preparation (IRP) were 4.2% higher. For comparison with 20 lyophilized coumarins, three sets of 20 artificially-depleted plasmas were selected in sequential order from the 60. The lyophilized coumarin plasmas gave a mean deviation of 9.6% from the fresh plasma calibration slopes compared with values of 2.0%, 6.1% and 11.7% for the three sets of 20 depleted plasmas. Although both types of lyophilized plasma calibration slopes give measurable differences from conventional fresh plasmas, these may be regarded as acceptable in clinical terms.

Original languageEnglish
Pages (from-to)462-467
Number of pages6
JournalBritish Journal of Haematology
Volume101
Issue number3
DOIs
Publication statusPublished - 1998

Keywords

  • Lyophilized plasmas
  • Thromboplastin calibration

ASJC Scopus subject areas

  • Hematology

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