Blood samples

[Frank_Stein]

This would also make changeling rounds more interesting. The original sample could out the changeling, but could easily be tampered with to frame others.

I don't think the blood samples should be able to show if someone is a changeling. Too much turbonerd potential. If you want to bloodtest someone, you need to manually draw their blood, which puts you at risk of being stung. For lore reasons we can say that a changeling snuck onto the station, absorbed someone, and assumed their identity after blood samples were taken but before the start of the shift.

I would say their original blood sample should show. If they were to absorb someone and assume their identity, that sample would have been the original crewman's and show as clean.

They could, however, take someone's clean sample and contaminate it with their own blood to confuse things, or reliable them, or just wipe everything