NEW WET VACUUM TOUCH DNA RECOVERY SYSTEM
M-Vac wet vacuum system improves the search and recovery of touch DNA.
Bob Milne MCSFS FFS takes a look at the wet vacuum DNA technique and results achieved by a number of Police services internationally.
Traditional swabbing is fine for the recovery of DNA from body fluids or the removal of cells on non-porous surfaces but what about the microscopic traces of body fluids or cells in crevices, in fabrics below the surface? Here swabs can be ineffective and that is why the M-VAC originally designed to recover bacteria from food plants for analysis was utilized in its present form to enable the more effective recovery of DNA.
A two-fold study by the Philadelphia Office of Forensic Science produced empirical data on the effectiveness of the wet vacuum M-Vac system. ln the first part the M-Vac recovered 180 times more than the swabbing of diluted buccal cells from clean cloth swatches. ln the second part of DNA recovery of touch DNA on a variety of substrates the M-Vac
recovery was on average 5 times more than swabbing in those scenarios.
Both validations however showed a significant increase in performance. The M-Vac enables the systematic search of clothing, rock, cement or other porous surfaces and even large-surface sampling from human skin. Both casework and research has shown traditional methods are not as effective as the M-Vac on these substrates.
M-Vac has been in use in the United States and other countries for a few years and a considerable number of current and cold solved cases have been published. The cases covered in this article serve to illustrate how effective the proper use of wet vacuum DNA recovery techniques can be.
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