how do companies such as the UFC test for IV infusions for rehydrations

Question

From what I understand an IV infusion is just to rehydrate the fighter after they’ve cut water weight for weigh ins. How is it possible for them to test to see if they’ve rehydrated through an IV infusion?

In: 3

Answer 1

They test for micro plastics that would have leeched into whatever they were rehydrating with from the IV bag.