{"id":686,"slug":"how-is-cell-viability-percentage-calculated","question":"How is cell viability percentage calculated?","intent":"procedure","language":"en","url":"https://worldwiki.io/q/how-is-cell-viability-percentage-calculated","entity":{"slug":"cell-viability","name":"Cell Viability","url":"https://worldwiki.io/entity/cell-viability"},"answer":{"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].","detailed_answer":"<p>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 <span class=\"ref\">[1]</span>.</p>","format":"paragraph","confidence":75,"verified_at":"2026-09-18 07:10:23","updated_at":"2026-09-18 16:10:23"},"sources":[{"id":134,"title":"Cell Viability Assays (Assay Guidance Manual)","url":"https://www.ncbi.nlm.nih.gov/books/NBK144065/","publisher":"National Center for Biotechnology Information (NCBI Bookshelf), Riss TL et al.","type":"journal","accessed_at":"2026-09-18 18:00:57"},{"id":135,"title":"Challenges of Cell Counting in Cell Therapy Products","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC11520012/","publisher":"Cell Transplantation (Liu M et al.)","type":"journal","accessed_at":"2026-09-18 18:00:58"},{"id":136,"title":"CAR T cell viability release testing and clinical outcomes: is there a lower limit?","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC6872962/","publisher":"Blood (Chong EA et al.), 134(21):1873–1875","type":"journal","accessed_at":"2026-09-18 18:00:58"},{"id":137,"title":"Quality standards for NK cell immunotherapies","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC12644036/","publisher":"Frontiers in Bioengineering and Biotechnology (von Werz et al.)","type":"journal","accessed_at":"2026-09-18 18:00:58"},{"id":138,"title":"Cell Viability – Flow Cytometry Facility","url":"https://flowcytometry.utoronto.ca/cell-viability/","publisher":"University of Toronto, Temerty Faculty of Medicine Flow Cytometry Facility","type":"academic","accessed_at":"2026-09-18 18:00:59"},{"id":139,"title":"Plasma membrane permeabilization following cell death: many ways to dye!","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC8289853/","publisher":"Cell Death Discovery (De Schutter E et al.)","type":"journal","accessed_at":"2026-09-18 18:00:59"},{"id":140,"title":"Assessing Adipocyte Viability and Surgeons' Work Efficiency by Comparing Different Liposuction Methods","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC10427077/","publisher":"Plastic and Reconstructive Surgery Global Open (Urbonas T et al.)","type":"journal","accessed_at":"2026-09-18 18:01:00"},{"id":141,"title":"Quantitative assessment of the impact of cryopreservation on human bone marrow-derived mesenchymal stem cells: up to 24 h post-thaw and beyond","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC7734731/","publisher":"Stem Cell Research & Therapy (Bahsoun S, Coopman K, Akam EC)","type":"journal","accessed_at":"2026-09-18 18:01:00"},{"id":142,"title":"Content and Review of Chemistry, Manufacturing, and Control (CMC) Information for Human Somatic Cell Therapy Investigational New Drug Applications (INDs)","url":"https://www.fda.gov/regulatory-information/search-fda-guidance-documents/content-and-review-chemistry-manufacturing-and-control-cmc-information-human-somatic-cell-therapy","publisher":"U.S. Food and Drug Administration","type":"government","accessed_at":"2026-09-18 18:01:00"}],"published_at":"2026-09-18 07:10:23"}