This can be done two ways:
1) Using a lua script and changing the GridRow.backcolorhttp://dragonrad.com/foswiki/bin/view/Help/DragonRADObjectTypes#GridRow
2) or it can be done with a Row Display Actions
The caveat with the Row Display Action is that the scanned value will have to be set in each row so that it can be compared to another column in the row. If they are not equal, the action can be setup to change a cell, or the entire row's backcolor.