Not a vet either but like any hospital, they prevent contamination every day. FIV test is available there. Felv/fiv/heartworm test is 30. Fiv is no joke. An ounce of prevention won't cure it, but maybe save others it comes in contact with. I been guilty too, not judging.
Honestly, I am not a vet, so I can't answer your questions thoroughly. But when they spay at a low cost clinic like this one they go by what you put down on the paperwork. They don't know your pet like a familiar vet would. So, if you didn't know, they didn't know. Did you ask for test? Also I don't know if there is any more risk at a spay clinic for a cat with FIV or not: this is a question for a qualified person.
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