Why is the MTT assay the most widely used cell proliferation assay?

The MTT assay is the most commonly used cell proliferation assay because it most accurately reflects the number of viable cells in a sample. It involves applying the MTT reagent directly to the cells and then measuring the cell proliferation by detecting the reduction of a yellow tetrazolium salt (MTT) into a purple formazan product by viable cells. This approach is favored for its simplicity and effectiveness across various cell types. MTT assays are also highly sensitive and have been adapted for use in high-throughput experiments.