ISSN:
1432-0584
Keywords:
Factor IX
;
Steam-treated factor IX concentrate
;
In vivo recovery
;
Half-life
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Factor IX (FIX) recovery and half-life was measured in ten hemophilia B patients under standardized conditions. Each patient received a steam-treated high-purity factor IX concentrate at a dose of 19–39 U/kg body weight. FIX activity was determined using a one-stage assay, which was calibrated against the international concentrate standard (reagents from Immuno, Heidelberg). The in vivo recovery ranged from 24% to 53% (mean value 37.7%) and the half-disappearance time (HDT) from 8–30 h (mean 16.7 h). In four of the ten patients, the distribution and elimination half-lives were estimated and ranged from 0.3 h to 3.9 h (mean 1.4 h) and from 28.6 h to 39.7 h (mean 33.1 h), respectively. In six patients FIX was redetermined using a different FIX deficient plasma and a plasma standard (reagents from Merz & Dade, Munich, FRG). Recoveries and HDT based on the results obtained with this method were significantly higher (68.2% vs 39.7%; p〈0.05), and longer (14.8 h vs 10.6 h; p〈0.05), respectively. FIX activity was also measured by both assay systems in 100 healthy subjects (50 males, 50 females). The reagents from Immuno yielded a mean value of 0.77 U/ml, while the mean FIX activity utilizing standards and reagents from Merz & Dade was 1.11 U/ml (p〈0.000001). The coefficient of correlation between the FIX activity measurements, as determined in 100 healthy subjects and 6 hemophilia B patients using the different test systems, was r=0.9 (N=159; y=0.08+1.3 * x; p〈0.001). Our data suggest that recovery and HDT of factor IX concentrate strongly depend on the assay and calibration conditions and that an international FIX activity plasma standard is urgently required.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00320754
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