Remediation techniques, such as irradiation, may damage plant cell walls resulting in extracellular cannabis DNA which the Grim Reefer enzyme will chew up.
Grim Reefer® enzyme degrades all extracellular DNA that is present in a sample prior to the lysis step.
This will naturally include some extracellular cannabis DNA that is present in your samples, but typical samples should include enough intracellular cannabis DNA for amplification on the HEX channel. This degradation of extracellular cannabis DNA explains why you may see a slight Ct shift in the HEX signal when comparing samples treated with and without Grim Reefer.
Remediation techniques meant to damage microbial cells may also damage plant cells and create more extracellular cannabis DNA. In that case, remediated cannabis samples treated with Grim Reefer may not produce as robust or any amplification in the HEX channel.
What to do when samples treated with Grim Reefer do not produce HEX signal
First, confirm that the Grim Reefer control produced an acceptable signal on the Cy5 channel. If not, that is an indication that the Grim Reefer enzyme was not properly inactivated, and therefore degraded the DNA that was exposed during the lysis step.
When only amplification of the Grim Reefer control is observed on Cy5 with no amplification on HEX, we recommend repeating the extraction without Grim Reefer and rerun the assay(s). If the reruns show HEX amplification it is likely that the cannabis DNA that is present in the sample is extracellular.