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How EHL Bio tests cell quality: sterility, viability and purity

The release tests a cell lot must pass before infusion

Quick answer

Before a lot is released, a GMP lab must test at least four things: sterility, mycoplasma, endotoxin, and the cells themselves — viability, cell count and the surface markers confirming they really are MSCs. These certificates are documents a patient is entitled to ask for.

Key facts

Positive markers
CD73, CD90, CD105
Negative markers
CD34, CD45
Typical viability spec
Commonly ≥80-90%
Document to request
Per-lot certificate of analysis

Sterility, mycoplasma and endotoxin

Sterility and mycoplasma testing is the basic safety gate: a nutrient medium that keeps cells alive for weeks is equally attractive to bacteria. Endotoxin is the bacterial wall fragment that can still trigger fever and inflammation even after the organism itself is dead.

Markers that confirm true MSCs

On the identity side, the accepted definition requires MSCs to be positive for CD73, CD90 and CD105 and negative for haematopoietic markers such as CD34 and CD45. Flow cytometry is what proves the product is mesenchymal stem cells and not a mixed cell population.

The per-lot document to request

Overseas patients should request the certificate of analysis for their own lot before infusion day. It states cell count, viability percentage and contamination results. A provider unable to produce lot-level documentation is a warning sign worth taking seriously.

Frequently asked questions

  • Can a patient see their own cell test results?

    Yes, and you should. It is the release document for a lot grown from your own cells, and any GMP-compliant provider keeps one.

  • What does low viability mean?

    Dead cells release no therapeutic signalling factors and add debris the immune system must clear, so a lot below the viability spec should not be released.

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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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