I took a Vyvanse at 6:45 am with a nature valley granola bar. I had to take a urinalysis at 8:30 am. Would I have enough d-amphetamine in my system to fail a urinalysis?

Vyvanse is a prodrug of amphetamine, which means the body must fully absorb the lisdexamfetamine (LDX) before the amphetamine is 'released'. I looked at the literature (my son takes this so I looked it up a few years back) and it takes 1 hour for the lisdexamfetamine to reach full effect (tmax). Then, it takes 3.5 hours for the d-amphetamine to reach tmax.  I pasted the info below from the leaflet that comes with the medicine.  (I also saw some info on fasting vs. Non-fasting and I don't think it much mattered, so your granola bar probably didn't do much). 

So, if you took it at 6:45am, you hit t-max at 7:45am, which is when the d-amphetamine would begin to appear.  Now, the d-amphetamine would not peak until after 11:00am, but you would have some d-amphetamine (45 minutes worth based on my basic analysis).  I know these tests vary in their precision, but, this is just my initial gut reation, I think even trace amounts will show up...but I'd like to see what other folks have to say.