6.2 Colorimetric assays
To measure cell metabolic activity, colorimetric tests rely on the
detection of a biochemical marker. A spectrophotometer can be used to
measure colorimetric cell viability because colorimetric test reagents
alter colour in response to cell viability. Colorimetric tests are
straight forward to conduct and reasonably priced. They can be used with
adherent or suspension cultures(Berg et al., 1994). The majority of
experimental protocols for these assays are included in the kit packages
for colorimetric test kits, which are offered by a variety of vendors.