Where possible, PeproTech obtains International Unit (IU) values through multiple side-by-side comparisons of our product(s) against the analogous WHO Reference Standard within our biological activity assay. Performing multiple comparison tests allows us to account for any outliers due to possible variations with the assay (e.g. product, handling, assay protocol, etc.). Using the results of these comparisons we can provide a reliable quantification of our product’s activity in relation to the activity of the WHO Reference Standard.
The IU values obtained by PeproTech are applicable across Lot Numbers of a specific Catalog Number as our testing covers multiple Lot Numbers of comparable activity. These values are based on comparison testing and are subject to change.
Bioassay Cell Line