EUROPEAN CONCERTED ACTION ON ANTICOAGULATION (ECAA) - THE MULTICENTERCALIBRATION OF RABBIT AND HUMAN ECAA REFERENCE THROMBOPLASTINS

Two candidate ECAA reference preparations have been calibrated in a mu lticentre exercise at 14 representative national laboratories to provi de reference thromboplastin for a large field study in 16 European cou ntries. Two preparations were required because of the established diff erences in ISI arising from the two main routes of calibration via rab bit and human IRP. To be comparable with working reagents in everyday use a human plain recombinant reagent of low ISI and a rabbit plain pr eparation of moderately high ISI were selected. A precise calibration of the two candidate preparations has been achieved with the manual PT technique and an ISI of 0.95 (SE 0.0078) for the human reagent and 1. 67 (SE 0.0322) for the rabbit reagent.