HIGH-SENSITIVITY DETECTION OF ACTIVATED FACTOR-IX - APPLICATION TO THE ANALYSIS OF DIFFERENT THERAPEUTIC FACTOR-IX CONCENTRATES AND PROTHROMBIN COMPLEXES
M. Kusch et al., HIGH-SENSITIVITY DETECTION OF ACTIVATED FACTOR-IX - APPLICATION TO THE ANALYSIS OF DIFFERENT THERAPEUTIC FACTOR-IX CONCENTRATES AND PROTHROMBIN COMPLEXES, Thrombosis and haemostasis, 79(4), 1998, pp. 778-783
A very sensitive and highly reliable test system for the detection of
activated coagulation factor IX (FIXa) has been established. This assa
y system is based on the cleavage of a fluorogenic substrate by activa
ted factor X (FXa) which is generated by FIXa. This assay can be used
to process a large number of samples at a time and, being based on the
convenient microtiter plate format, can easily be adapted to automate
d processing for routine screening of large sample numbers. With this
assay at hand we determined the FIXa content of different commercially
available therapeutic FIX sources, such as high purity FIX (HPFIX) an
d prothrombin complex concentrates (PCC). Here we demonstrate that PCC
from several suppliers do not contain significantly higher levels of
FIXa as compared to HPFIX from the same supplier. in fact, there is a
tendency for HPFIX to contain more FIXa than PCC. Moreover, HPFIX from
certain manufacturers who do not produce PCC are characterized by an
exceptionally high content of FIXa. Therefore, the higher thrombogenic
potential of PCC which is well documented clinically cannot be explai
ned solely - if at all - by an increased content of FIXa. Rather, it w
ill be necessary to identify other components responsible for this phe
nomenon.