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Membrane integrity—based cell viability assay

The SYTOX® Dead Cell Stains are nucleic acid stains for assessing cell viability with flow cytometry. Dead cells have bright fluorescence and live cells have dim fluorescence. SYTOX® Dead Cell Stains are available in five different colors.

This protocol can be used for:

  • Identifying live and dead cells using a flow cytometer

This protocol should not be used for:

  • Fluorescence microscopy

You will need the following for this protocol:


1. Thaw vial of dye
2. Add 1 mL cells to a flow cytometer tube
3. Add 1µL dye to cells and mix well
4. Incubate for 15 minutes
5. Run cells on a flow cytometer


Protocol tips

  • Cell concentration should be 5 x 107 cells per mL
  • No washing is required after staining
  • Not compatible with fixation
  • Dye stock solutions should be stored frozen
Spectral information and storage
Excitation/Emission (in nm)444/480488/525547/570546/647640/658
Flow cytometer channelDAPIFITCPEPerCPAlexa Fluor® 647
Storage conditions–20°C–20°C–20°C–20°C–20°C
Cat. No.S34857S34860S34861S10349S34859
The SYTOX® Dead Cell Stain Sampler Kit (Cat. No. S34862) contains trial-sized samples of 5 different stains (50 tests per stain) to help researchers identify the best stain for their multicolor experiments.

5-panel graph showing cell viability of Jurkat cells labeled with each of the SYTOX® Dead Cell stains

A mixture of heat-killed and live Jurkat cells were labeled with the SYTOX® Dead Cell stains. All stains were labeled according to the listed protocol. Samples were analyzed on a flow cytometer equipped with a 488 nm laser, a 405 nm laser, or a 633 nm laser, and fluorescence emissions were collected using the appropriate filters.