Most likely those are controls for testing the machines for accuracy. In medical facilities it is required to test daily for accuracy. For instance glucose monitoring machines are tested with a positive and negative solution to make sure the machine registers these correctly.

I'm not judging you but "most likely" does concerns me.

Since I am not in possession of these controls and can not say for sure; this is why I said most likely. Based on 50 years as an RN and knowing that machines have to be tested with controls, this is most likely what it is.😉