In that case, you're doing the right thing with the vet appt and keeping the sample. Even if it is just a weird urates, it'll be good to get such confirmation from a vet who has seen and handled it personally. All we can do here is guess based on vague descriptions.

In the meantime...I don't think there is anything special you need to do for the snake. Just leave her be and don't do anything to add to her stress. The less handling, the better, until you're certain she's healthy.

Good luck. Let us know what the vet says.