THE EUROPEAN CONCERTED ACTION ON ANTICOAGULATION (ECAA) - FIELD STUDIES OF COAGULOMETER EFFECTS ON THE ISI OF ECAA THROMBOPLASTINS

Local calibration studies have been performed with lyophilized plasmas at 155 European laboratories to assess coagulometer effects on manual ISI of ECAA thromboplastins (low ISI human recombinant and high ISI r abbit brain). Common sets of 7 normal and 20 artificially depleted lyo philized plasmas were tested with the thromboplastins in the routine l ocal coagulometers. With the human reagent, marked lowering of the man ual ISI resulted with most coagulometers, which was associated with di sproportionate shortening of the normals. Where this shortening did no t occur, there was little coagulometer effect on the ISI. With the rab bit reagent, proportionate shortening with both normal and abnormal pl asmas occurred in most instruments with little effect on ISI. INR corr ection by local ISI assignment appeared successful with the ECAA human reagent. There was negligible INR correction from local calibration o f the ECAA rabbit reagent in coagulometers where thromboplastin ISI we re unchanged from the ECAA established manual values.