Purity = The percent of the total sample recovered that is from the actual area dissected.  The reciprocal would be percent of the recovered sample that is from outside the dissected area.

Method and result: Sections were cut from  a mouse-human FFPE tissue fusion block that was generated by casting  mouse and human tissue in close proximity. These sections were partially deparaffinized, then dissected at the indicated distances from the fusion line. The recovered tissue was completely digested using the xTractr/THOR system, then subject to either endpoint or real time PCR analysis using amplicons to the mouse and human Cox1 gene region of the mitochondrial DNA sequence.

These results suggest the purity is greater than 99% when dissecting tissue as close as 100 microns of a potential contaminating tissue.  Dissecting partially deparaffinized rather than fully deparaffinized tissue generally aids in improving purity (data not shown).