Well Number signal from serum sources of LDH found in supplemented growth media [47, 48] . Exogenous sources of LDH greatly elevate background values and negatively impact the overall signal window. This experimental detriment can be largely mitigated by careful pre-screening of serum sources for cell culture prior to LDH assay. LDH assays are also subject to assay artifacts by compounds that inhibit the LDH activity and by standard fluorescence and color quenching interferences [49] [50] [51] .