Check out Overview - EPI * Exocrine Pancreatic Insufficiency
There is information there on:
To diagnose those there is a 12 hour fasting blood test that goes to Texas A/M (typically).
It could be coccidia: Coccidia
which is what I am thinking they said it was?
Or here are others:
CDC - Parasites - Alphabetical Index of Parasitic Diseases
Those things might show up on a fecal test, or a fecal PCR test: CDC - Parasites - Alphabetical Index of Parasitic Diseases
I did have a dog with giardia years ago, which has a different treatment, and she was like a garden hose.
ONE drink out of a puddle! ONE! Now my dogs know they aren't allowed.
Sounds like you want more info and good for you.