Although we recommend up to 500 ng in the data card this is only a generalization. The amount of DNA that can be repaired depends on many factors, such as the type of damage or damages and the total amount of damage. We have repaired 1 µg of DNA using 1 µL of the PreCR Repair Mix enzyme cocktail and we do not consider this to be the actual upper limit. The flip side to this question is how little DNA is safe to use with the PreCR Repair Mix. We have not found a lower limit of DNA concentration for repair. Typically, the concentration of DNA in the PreCR Repair Mix reaction is not a significant concern for performing the reaction.