Japanese–English glossary
Passage number
継代数keidaisū
The number of times cells have been subcultured, used as a record of their culture history. As passages accumulate, cells can drift, and variants with a growth advantage can take over, affecting productivity and quality. Cell banks record the passage number or population doubling level, and the limit of in vitro cell age for production is set and supported by data on the stability of the cell line (ICH Q5D).