Why over-expanded cells lose their punch
Quick answer
Each time cells are moved to fresh culture vessels counts as one passage. The higher the passage, the closer cells drift to senescence: slower division and weaker secretion of therapeutic factors. Good labs therefore cap passage number and test potency per lot rather than counting cells alone.
A common misconception is that more cells is always better. In reality, a large number produced by excessive expansion can be weaker than a smaller dose of younger cells, so ask both the cell count per dose and the passage number used.
Potency testing checks that the cells still function — for example their ability to suppress immune cell proliferation, or how much growth factor they secrete. That is the line between a lab operating to pharmaceutical standards and one that reports only cell counts.
Other quality drivers include donor age, comorbidities, smoking and the culture medium formulation. A centre processing thousands of lots a year, as EHL Bio does, has the accumulated data to tune protocols to each patient's cells.
Protocols differ, but the lab should state a defined cap and back it with potency data.
They remain usable, but average growth is slower, so dose planning or culture time may need adjusting.
Each time cells are moved to fresh culture vessels counts as one passage. The higher the passage, the closer cells drift to senescence: slower division and weaker secretion of therapeutic factors. Good labs therefore cap passage number and test potency per lot rather than counting cells alone.
One passage: One subculture step
5 points • reviewed 2026-08-28
Reviewed and last updated: 2026-08-28
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Last updated: 2026-08-28 · This content is for information only and is not medical advice. Consult a qualified doctor before making treatment decisions.
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