---
title: "How is cell viability percentage calculated?"
url: "https://worldwiki.io/q/how-is-cell-viability-percentage-calculated"
type: "question"
language: "en"
intent: "procedure"
entity: "Cell Viability"
topic: "SVF & Adipose-derived Cells"
published: "2026-09-18 07:10:23"
updated: "2026-10-08 09:18:06"
---

# How is cell viability percentage calculated?

## Short answer

Viability percentage = viable cells ÷ total cells counted × 100. With dye exclusion, unstained cells count as viable and stained cells as dead. This can be done manually on a hemocytometer or with an automated counter using trypan blue or AO/PI. The viable cell count, as an absolute number or concentration, is usually reported alongside the percentage, because a high percentage can still mean too few cells [2][3].

## Answer

Plate-reader assays such as MTT, resazurin or ATP give a relative signal, not a per-cell percentage. They are usually expressed as a percentage of an untreated control [1].

### Stem cells in cosmetic surgery

In cosmetic surgery, "stem cell" procedures almost always use [adipose-derived stem cells](/entity/adipose-derived-stem-cell). The stromal vascular fraction (SVF), which contains them, is separated from liposuctioned fat and mixed into the fat being grafted, as in [stem cell breast augmentation](/entity/stem-cell-breast-augmentation) and [stem cell fat grafting](/entity/stem-cell-fat-grafting).

## Related questions

- [Trypan blue vs MTT: which cell viability assay should I use?](https://worldwiki.io/q/trypan-blue-vs-mtt-which-cell-viability-assay-should-i-use)
- [Does higher cell viability mean better fat graft survival?](https://worldwiki.io/q/does-higher-cell-viability-mean-better-fat-graft-survival)
- [Why does cell viability drop after thawing cryopreserved cells?](https://worldwiki.io/q/why-does-cell-viability-drop-after-thawing-cryopreserved-cells)
- [What is an acceptable cell viability for cell therapy products?](https://worldwiki.io/q/what-is-an-acceptable-cell-viability-for-cell-therapy-products)

## 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