---
title: "What is an acceptable cell viability for cell therapy products?"
url: "https://worldwiki.io/q/what-is-an-acceptable-cell-viability-for-cell-therapy-products"
type: "question"
language: "en"
intent: "informational"
entity: "Cell Viability"
topic: "SVF & Adipose-derived Cells"
published: "2026-09-18 07:10:23"
updated: "2026-09-18 16:10:23"
---

# What is an acceptable cell viability for cell therapy products?

## Short answer

For cell therapy products, the FDA generally expects a minimum viability specification above 70%, and sponsors must justify a lower limit with data [2]. NK-cell trials in the US and Europe used ≥70% across the board [4]. Some products use stricter limits. The commercial specification for the CAR T product tisagenlecleucel is at least 80%, although a 2019 analysis found no link between viability below 80% and remission rates [3].

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## Sources

1. [Cell Viability Assays (Assay Guidance Manual)](https://www.ncbi.nlm.nih.gov/books/NBK144065/) — National Center for Biotechnology Information (NCBI Bookshelf), Riss TL et al. · evidence page: https://worldwiki.io/source/134
2. [Challenges of Cell Counting in Cell Therapy Products](https://pmc.ncbi.nlm.nih.gov/articles/PMC11520012/) — Cell Transplantation (Liu M et al.) · evidence page: https://worldwiki.io/source/135
3. [CAR T cell viability release testing and clinical outcomes: is there a lower limit?](https://pmc.ncbi.nlm.nih.gov/articles/PMC6872962/) — Blood (Chong EA et al.), 134(21):1873–1875 · evidence page: https://worldwiki.io/source/136
4. [Quality standards for NK cell immunotherapies](https://pmc.ncbi.nlm.nih.gov/articles/PMC12644036/) — Frontiers in Bioengineering and Biotechnology (von Werz et al.) · evidence page: https://worldwiki.io/source/137
5. [Cell Viability – Flow Cytometry Facility](https://flowcytometry.utoronto.ca/cell-viability/) — University of Toronto, Temerty Faculty of Medicine Flow Cytometry Facility · evidence page: https://worldwiki.io/source/138
6. [Plasma membrane permeabilization following cell death: many ways to dye!](https://pmc.ncbi.nlm.nih.gov/articles/PMC8289853/) — Cell Death Discovery (De Schutter E et al.) · evidence page: https://worldwiki.io/source/139
7. [Assessing Adipocyte Viability and Surgeons' Work Efficiency by Comparing Different Liposuction Methods](https://pmc.ncbi.nlm.nih.gov/articles/PMC10427077/) — Plastic and Reconstructive Surgery Global Open (Urbonas T et al.) · evidence page: https://worldwiki.io/source/140
8. [Quantitative assessment of the impact of cryopreservation on human bone marrow-derived mesenchymal stem cells: up to 24 h post-thaw and beyond](https://pmc.ncbi.nlm.nih.gov/articles/PMC7734731/) — Stem Cell Research & Therapy (Bahsoun S, Coopman K, Akam EC) · evidence page: https://worldwiki.io/source/141
9. [Content and Review of Chemistry, Manufacturing, and Control (CMC) Information for Human Somatic Cell Therapy Investigational New Drug Applications (INDs)](https://www.fda.gov/regulatory-information/search-fda-guidance-documents/content-and-review-chemistry-manufacturing-and-control-cmc-information-human-somatic-cell-therapy) — U.S. Food and Drug Administration · evidence page: https://worldwiki.io/source/142