It’s subtle, but this wafer is just slightly pink over most of the surface. Probably nothing you would notice if you were just checking on it in a dark tabernacle. But it’s growing Serratia.

Which means I expect it to be nicely red in a couple days, maybe even with the dark gooey clots after about a week. But I’m running out of experiments I want to try. Does anyone have any suggestions?

I can’t check blood type easily because I think the standard at home kits rely on the sample being fresh blood so that it will agglutinate. For this I would need a test for dried blood or other tissue like they do in forensic labs. That’s going to take a bit more research.