Welcome! My name isXXXXX am a 2003 graduate, and currently a Medical Director of a veterinary hospital.
I am sorry to hear about this concern for Lucy.
You have to be automatically concerned.
Toxicity from grapes is a type of problem that once it affects the body, reversing the toxicity in the kidneys can be difficult.Raisin toxicityRaisin toxicity 2
The two above links will help to explain why.
If it was only a few grapes, than the amount of exposure is quite low.
But, if it was a bunch of grapes, you should consult an emergency vet immediately.
There is more information about how much can be toxic
above, although we don't know exactly as some pets can be hypersensitive.
I hope that information has been helpful.
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