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.
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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