Intrinsic chemiluminescence, accompanying biochemical reaction in living cells and tissues, exhibits extremely low intensity, which is the main barrier in the usage of this luminescence for analytical purposes. In the presence of specific compounds, called CL enhancers, the CL intensity in reactions of reactive oxygen species and during lipid peroxidation can be amplified by 3-5 orders of magnitude.
The bioluminescence originates from chemical transformation of specific low-molecular compounds called luciferins catalyzed by special enzymes called luciferases. Both chemiluminescence and bioluminescence have been used in analytical biochemistry, in particular in clinical laboratory analyses.