The importance of the determination of cell viability has prompted the development of several assays of viability that utilize the exclusion of certain dyes by viable cell membranes. Recently, flow cytometry has been adapted to estimate cell viability by using fluorescent dye which is excluded by living cells on the basis of altered dead cell properties.

We have developed a flow Cytometric method for measuring cell viability after staining with propidium iodide (PI) and have compared it with the classical colorimetric method, MTT assay, which is currently widely used in cytotoxicity assays in the research field.

We performed flow cytometry and MTT assay for the comparison of the sensitivity of the assessment of cell viability.

Decrease of cell viability was measured by flow cytometry with the addition of as little as 0.002% Triton-X 100 in comparison to MTT assay which could only reveal a similar decrease of cell viability with the new method to 0.008% Triton-X 100.

Our results demonstrate this new method to be more sensitive and simple for the assessment of cell viability.