A definite doube lunger will leavea morepinksh bubbly blood, but if there is heart blood mixed in, that may make it one homogenous color. Liver hits tend to leave a much darker blood. IT is not as if one blood is not recognizable from the other because the colors are so different, just subtle variations that can lead to clues as to where the animal was hit. Usually the arrow will tell more of the story. My double lunger this year left the fletching covered in bubbly blood, while the heart shot was bright red, but no bubbles.