https://www.amazon.com/Reptiles-Rabb.../dp/B000J5SOZ4
https://perfectpetproducts.com/SAVE-...ME-7850012.htm
I'd probably trust the one for reptiles and amphibians more than the all animal one, but I am not sure.
I just googled "reptile fecal mail in."
I've heard from others that have done this, but not sure what they used (i.e. test kit).
I would think do this first and then a vet to safe stress, but it also depends how worried you are and how comfortable you are with your vet and their expertise with reptiles.