Summary
An international collaborative study was carried out to determine the suitability
of freeze-dried preparations of β-TG and PF4 to serve as international standards,
and to compare these materials with other purified preparations and with plasma samples.
Although problems remain with the accurate measurement of these proteins, it has been
demonstrated that common standards improve the precision of measurement by RIA and
provide an essential foundation for future work into the effects of assay system differences.
The World Health Organization established in 1984 the purified preparation of β-TG
(83/501) and the purified preparation of PF4 (83/505) as International Standards,
with assigned potencies of 500 International Units per ampoule and 400 International
Units per ampoule, respectively.
Key words
β-thromboglobulin - Platelet factor 4 - International Standards - Radioimmunoassay
