TY - JOUR
T1 - The importance of 'like to like' ISI calibrations with freeze dried plasmas
AU - Poller, L.
AU - Van Den Besselaar, A. M H P
AU - Jespersen, J.
AU - Tripodi, A.
AU - Houghton, D.
PY - 1998
Y1 - 1998
N2 - Aim - To assess reliability of like to like and cross species calibrations using two types of certified freeze dried plasma calibrants- artificially depleted of vitamin K clotting factors, and from coumarin treated patients. Methods - Six ECAA national control laboratories provided certified values for the freeze dried plasmas in terms of the human plain international reference preparation (IRP) (BCT/441) with the manual prothrombin time technique. Eight other ECAA national laboratories determined international sensitivity index (ISI) values in full fresh plasma same species and cross species WHO calibrations against a low ISI human IRP (BCT/441) of the ECAA low ISI human thromboplastin and high ISI ECAA rabbit thromboplastin. Parallel calibrations were performed using the certified values. Results - Calibrations on fresh plasmas of the human ECAA reference thromboplastin (stated ISI = 0.95) gave ISI of 0.957 against the human IRP and 1.66 against the rabbit IRP. The ECAA rabbit (stated ISI = 1.67) gave an identical value on the fresh plasma calibration v the human IRP. With freeze dried depleted plasmas certified in terms of the human IRP, the ISI of the ECAA human was 1.01, but the ECAA rabbit (stated ISI = 1.67) gave a low ISI of 1.47. The freeze dried coumarin plasmas gave an ISI of 0.943 for the ECAA human but only 1.493 for the ECAA rabbit. Conclusions - Fresh plasmas give reliable ISI when calibrating thromboplastins in same species and cross species calibrations. Freeze dried plasmas certified in terms of a single IRP, whether artificially depleted or of coumarin plasma origin, cannot be used for calibration of dissimilar thromboplastins.
AB - Aim - To assess reliability of like to like and cross species calibrations using two types of certified freeze dried plasma calibrants- artificially depleted of vitamin K clotting factors, and from coumarin treated patients. Methods - Six ECAA national control laboratories provided certified values for the freeze dried plasmas in terms of the human plain international reference preparation (IRP) (BCT/441) with the manual prothrombin time technique. Eight other ECAA national laboratories determined international sensitivity index (ISI) values in full fresh plasma same species and cross species WHO calibrations against a low ISI human IRP (BCT/441) of the ECAA low ISI human thromboplastin and high ISI ECAA rabbit thromboplastin. Parallel calibrations were performed using the certified values. Results - Calibrations on fresh plasmas of the human ECAA reference thromboplastin (stated ISI = 0.95) gave ISI of 0.957 against the human IRP and 1.66 against the rabbit IRP. The ECAA rabbit (stated ISI = 1.67) gave an identical value on the fresh plasma calibration v the human IRP. With freeze dried depleted plasmas certified in terms of the human IRP, the ISI of the ECAA human was 1.01, but the ECAA rabbit (stated ISI = 1.67) gave a low ISI of 1.47. The freeze dried coumarin plasmas gave an ISI of 0.943 for the ECAA human but only 1.493 for the ECAA rabbit. Conclusions - Fresh plasmas give reliable ISI when calibrating thromboplastins in same species and cross species calibrations. Freeze dried plasmas certified in terms of a single IRP, whether artificially depleted or of coumarin plasma origin, cannot be used for calibration of dissimilar thromboplastins.
KW - Freeze dried plasma
KW - International sensitivity index
KW - Species specificity
KW - Thromboplastin
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M3 - Article
C2 - 9659238
AN - SCOPUS:0031867279
SN - 0021-9746
VL - 51
SP - 275
EP - 279
JO - Journal of Clinical Pathology - Clinical Molecular Pathology
JF - Journal of Clinical Pathology - Clinical Molecular Pathology
IS - 4
ER -