Well the PGM enzyme was negative, and the AK enzyme is also found in animals, and 17 out of 20 markers means it could be half the world plus little green men on Mars.
I think it's best all round to simply say it was not Sheila's blood in the silencer and whoever put the blood in it got lucky with the blood group matching Sheila's.
What is unusual about the PGM eynzyme test coming up negative?
The exhibits were first tested for the presence of blood and whether it was human in origin so the idea the AK enzyme originated from some non-human species is out of the question since it was confirmed as human in origin.
I have already explained the CoA confirmed the 17/20 markers are meaningless and concluded it was not possible to say either way whether or not Sheila's DNA was in the silencer. The court further concluded Sheila's blood was in the silencer (flake/blood groupings) but that it was all swabbed away in the course of testing hence the later LCN DNA tests came up inconclusive.