Membrane integrity—based viability assay

The Invitrogen LIVE/DEAD fixable dead cell stains distinguish between live and dead cells in flow cytometry. The dyes covalently bind to intracellular and extracellular amines, allowing the staining pattern to be preserved following formaldehyde fixation. Choose from eight different fluorescent 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. Dilute LIVE/DEAD fixable dead cell stain by adding 50 µL DMSO to vial
3. Add 1 mL of cells to a flow cytometer tube in protein-free buffer
4. Add 1 µL of diluted stain to cells
5. Mix cells and stain
6. Incubate 30 minutes
7. Wash cells
8. Analyze on flow cytometer


Protocol tips

  • Cell concentration should be 1x104 to 1x106 cells per mL
  • Washing is required after staining
  • Cell staining is preserved after fixation, but fixation is not required
  • Dyes are provided in single-use vials and should be discarded after use

Histogram showing live and dead cells distinguished using the LIVE/DEAD fixable dead cell stain kit reagents
Live and dead cells distinguished by flow cytometry using the LIVE/DEAD Fixable Violet Dead Cell Stain Kit.

Emission specifications

LIVE/DEAD dye Excitation source Ex* Em*
Blue fluorescent (Cat. No. L23105) UV 350 450
Violet fluorescent reactive dye (Cat. No. L34955) 405 nm 416 451
Aqua fluorescent (Cat. No. L34957) 405 nm 367 526
Yellow fluorescent (Cat. No. L34959) 405 nm 400 575
Green fluorescent (Cat. No. L23101) 488 nm 495 520
Red fluorescent (Cat. No. L23102) 488 nm 595 615
Far red fluorescent (Cat. No. L10120) 633/635 nm 650 665
Near-IR (Cat. No. L10119) 633/635 nm 750 775
Sampler kit containing all 8 dyes (Cat. No. L34960) See individual dye
* Approximate fluorescence excitation (Ex) and emission (Em) maxima, in nm.