[2] Touch DNA analysis only requires seven or eight cells from the outermost layer of human skin.
[3] The technique has been criticized for high rates of false positives due to contamination—for example, fingerprint brushes used by crime scene investigators can transfer trace amounts of skin cells from one surface to another, leading to inaccurate results.
[6] The technique is very similar to Low Copy Number DNA analysis, to the extent that court rulings have sometimes confused the two.
[7] Touch DNA relies on the STR analysis of cells collected off of objects.
[8] Upon collection, the cells' DNA is extracted, and 13 genomic locations that vary among individuals are assessed to confirm suspects or exonerate those that are innocent.