Fecal analysis is not the only diagnostic available for herps! Parasites are not the only illness either!

1)Whatever vet you end up using, let them know how far you're prepared to go to save your gecko. Bloodwork would be my next choice of tests, and will involve sedation so as to not have the tail drop while sampling. Often symptomatic treatment is done while a diagnoses is yet to be found and will likely be necessary to keep your critter alive.

2)Verify your husbandry and troubleshoot where it can be improved. It can always be improved, even if there are no obvious flaws.

Ian

If this was a cat or a dog, it would be hospitalized.