If all of these assays are giving unlooked-for results, there is likely an issue with the materials or the instrument rather than any one procedure.

We recommend investigating these common causes:

• Reagents may not have been stored correctly. Check to ensure that accidental refreezing did not occur.

• Cell medium may be contaminated or unsuitable for sample. Stable, healthy cells will give more useful data. Use a different media and run assay again.

• The chosen modality might not be suitable for the experiment. Perform an assay using a different format (colorimetric or fluorimetric) to see if results reflect expectations.