What is the trypan blue exclusion method?
Trypan blue is a vital dye that cannot penetrate healthy cell membranes but enters dead or damaged cells, staining them blue. Viable cells remain unstained and appear bright under the microscope. See also our calculate OD600 to Cell Number Cell Concentration.
Why do I need to count multiple squares on the hemocytometer?
Counting multiple squares (typically 4 or 5) provides better statistical accuracy and reduces counting error. It gives a more representative sample of your cell suspension.
What dilution factor should I use with trypan blue?
The standard dilution factor for trypan blue staining is 2:1 (equal volumes of cell suspension and 0.4% trypan blue), giving a dilution factor of 2.
What is considered good cell viability?
Generally, >90% viability is excellent, 80-90% is good, 70-80% is fair, and <70% is poor. However, acceptable viability depends on your specific application and cell type.
How is the hemocytometer factor calculated?
The standard hemocytometer factor is 10,000 (1×10⁴), which converts the average cells per large square to cells per mL, accounting for the chamber's volume and dimensions.
Can this calculator be used for different cell types?
Yes, this calculator works for any cell type that can be stained with trypan blue, including mammalian cells, yeast, and some bacterial cells.
What if I counted a different number of squares?
The calculator accounts for the number of squares counted in its calculations. You can select 1, 4, or 5 squares depending on your counting method. You might also find our MOI (Multiplicity of Infection) Calculator useful.