Biopsy samples from animals or patients may also be submitted for a Comet Assay. Lymphocytes from early Phase I clinical trials can provide information to help assess decision points. Serial biopsy samples can also be used to give an indication of effect over time of a treatment. Collection of tissues for a Comet Assay can also provide early evidence of the effect on DNA breakage in early studies evaluating the toxicology risks of a compound.