Blood tests while on Imuran?

I'm going to be starting Imuran in a week or so and I wanted to be sure my GI is ordering the right types of blood tests. I've heard some horror stories about some important indicators being missed because of poor testing.

Anyone know which areas are the most important to check? I read about something called a Prometheus test? I was only diagnosed recently and all of this is coming at me really quick and I really ain't got clue

Tornado is exactly right. usually they run the prometheus test only in the beginning to see whether you're in the correct range for the medicine, later on, you will not have to have that test. The regular blood work is just the CBC and liver panel. Some doctors don't even do the prometheus test because it's expensive (and may not be covered by insurance) and your symptoms can be an indication of whether the medication is working. I am happy i had all the tests because my numbers were always extremely low and my regular liver tests didn't show anything off. The metabolites test, on the other hand, did. I get my CBC/hepatic panel every few months - it's been stable for a long time and I haven't changed doses.