I took J.D. into the vet the first time when he was acting "off", and I told them I wanted a Spec fPL test, complete blood work up, some cyproheptadine, prescriptions for ondansetron and buprenex, and asked about whether they thought fluids would help. They ended up trying to charge me $120.00 for their "in house" snap pancreatitis test. I called them when I read the receipt when I got home, and told them "I did not order that test. I want a Spec fPL" and I told them that "I would pay the difference between the two tests". Luckily they had saved some blood and were able to send off a sample for the Spec fPL, and that test only cost $80.00, so they ended up owing me money ;-) .
Ondansetron was $33.00 for 10 pills at my grocery store pharmacy, and is less than $33.00 for 90 pills at the Costco Pharmacy (you do not need a membership to use their pharmacy). So Costco is way less expensive if you end up using ondansetron.
The anti-nausea drug with the appetite stimulant, and sometimes pain relief, helps J.D. Some cats need fluids too.
The test is supposed to be a fasted test, but my vet wanted him tested right then, the last time. So it wasn't fasted the second time.
Anyway, I was just letting you know how to save some money, and some of our experience.
I think you might want to try a different vet if you are not comfortable with the answers you received from the last one. The one you just went to said there would be bloody diarrhea and vomit. That is not our experience and I have not heard of those symptoms. Maybe others have.