LCN is used on items in cases where only minimal contact has occurred or there are only small quantities of cells/DNA present. Unlike touch DNA, these samples are processed through a higher number of polymerase chain reaction (PCR) cycles which may be able to obtain a DNA profile when conventional PCR cannot. LCN is usually only used on a sample that has already been processed and has an indication of the presence of DNA, but cannot be re-worked any further using standard DNA methods.
Bode Cellmark uses a touch evidence procedure for processing samples from areas where you would expect to find DNA (in the form of skin cells) from a person who has come in contact with the item. An example is the handle of a murder weapon or a pair of pants that have been pulled down. The success of touch DNA depends on the sampling method, the type of material, and the shedding capabilities of the suspect, as some people naturally leave behind more skin cells.
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