The key biochemical signal comes from metabolically active cells, whose mitochondrial dehydrogenases reduce WST-1 tetrazolium salt to a colored formazan product. This conversion links cellular metabolic activity to a measurable color change rather than requiring a radioactive label. Measuring the resulting absorbance provides a quantitative basis for comparing cellular responses across experimental conditions.
Absorbance generally reflects the number of viable cells because active cells produce the colored formazan product. However, the signal is generated through cellular metabolic activity, so comparisons also indicate differences in the metabolic state associated with each condition. This distinction matters when evaluating treatments, immune responses, or pathogen effects on cellular health.
Its nonradioactive format supports measurements of cell viability and proliferation without relying on radioactive detection. The assay also fits microplate workflows, allowing researchers to compare multiple experimental conditions in screening or comparative studies. These features make it useful when investigating pathogen-induced damage or treatment effects while maintaining a colorimetric readout.
After viable, metabolically active cells generate formazan, researchers measure the color intensity by spectrophotometry. Absorbance values can then be compared across cells exposed to pathogens, immune-related conditions, or compounds. In a microplate workflow, this approach supports parallel comparative experiments and helps identify differences in cellular health or proliferation between tested conditions.
Researchers can use the assay to evaluate how pathogens affect the health of cultured cells by comparing the metabolic viability signal between experimental conditions. A reduced colorimetric response generally indicates fewer viable or metabolically active cells. This makes the method suitable for quantifying pathogen-associated cytotoxicity within broader immunology and infection experiments.
The method can compare cellular responses in the presence of antimicrobial or immunomodulatory compounds, helping assess how treatments influence cell health. It can also be used alongside infection-focused experiments to examine treatment-associated changes in viability or proliferation. Because measurements are compatible with microplate workflows, the assay supports comparative studies and screening across multiple conditions.