Touch DNA is usually not visible and
since it is often deposited in smaller amounts than the DNA found in
bloodstains or other body fluids, it is more difficult to obtain DNA profiles
from these samples. The key to obtaining successful Touch DNA results depends
on awareness of items, which may be suitable for Touch DNA analysis and using
the sampling technique or collection method that will recover the highest
number of skin cells.
- Swabbing: Surface of the item is
rubbed with a cotton swab to collect possible cells. This method is
preferred for hard items such as glass or plastic.
- Cutting: May be used for soft
items, such as clothing, in which fabric from areas of interest is cut to
collect possible cells.
- In addition to the commonly used
swabbing and cutting methods, latest technologies have recently started
using the "Scraping" and "Tape Lift" methods, in which
the surface of soft items such as clothing are either scraped with a
blade, or sampled with a small piece of tape, to collect possible cells.
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