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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 1 µL 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/Emission444/480 nm488/525 nm547/570 nm546/647 nm640/658 nm
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.