Trypan Blue Staining

Trypan Blue is a dye commonly used to assess cell viability.

Trypan Blue solution, 0.4%
Hemocytometer with brightfield/phase microscope or automated cell counter (i.e. Countess™ automated cell counter)

Note on Trypan Blue

  • Trypan Blue is toxic to cells. After adding Trypan Blue dye to cells, move quickly to determine cell viability.


  1. Add 10 µL of 0.4% Trypan Blue to 10 µL washed cells. Pipette to mix.
  2. Transfer 10 µL of cell-Trypan Blue mix to a counting slide.
  3. View under brightfield/phase microscope or cell counter.
  4. Assess cell morphology and viability and troubleshoot as needed.
    1. Viable cells are impermeable to Trypan Blue and will exclude the dye (Trypan Blue negative; Figure A).
    2. Dead cells are permeable to Trypan Blue and will stain Trypan Blue positive (Figure A).
    3. Isolated nuclei will stain Trypan Blue positive (Figure B).

Figure. (A) Washed K562 cells are mostly viable (bright white and round). A dead cell (blue, Trypan positive) is circled in red. (B) Successful nuclei harvest shows Trypan Blue stained nuclei. An intact cell (bright white, Trypan negative) is circled in red.

Did this answer your question? Thanks for the feedback There was a problem submitting your feedback. Please try again later.