Summary
An international collaborative study, in which 22 laboratories participated, was carried
out to establish a replacement for the International Standard for Heparin. A total
of 248 assays were analyzed, including APTT, thrombin inhibition and anti-Xa assays,
as well as pharmacopoeial assays. Overall, there was less than 5% difference in the
mean potency estimates of the candidate preparations, by all assay methods. The freeze-dried
preparation 82/502 demonstrated the closest parallelism by bioassay to the existing
standard and was established by WHO as the 4th International Standard for Heparin,
with an assigned unitage of 1780 i.u. per ampoule.
Keywords
Heparin - Standard
