A Plan

I finally got to speak with Josie's neurologist this afternoon and I feel a lot better about everything. She told me that an arterial stick is very painful (she's had them personally on her) and that she would not want to put Josie through that unless absolutely necessary. At this point, she thinks that it would be fine to wait until the next urinalysis comes back to make that decision. If the glycine level should come back the same (slightly elevated) or even more elevated, then Josie will see a Metabolic Disorder Specialist (not an endocrinologist like one nurse told me). From there, we will decide whether to try labs again. The neurologist also wants me to move Josie's next appointment from April to March so that she can re-evaluate her sooner. She also told me to call her two weeks after we drop the urine sample off and that she would call and try to get it pushed through faster (something the nurse made it sound like was not possible) so that we would have the results before her next appointment. In the mean time, we are just supposed to watch for any negative changes in Josie (lack of energy, sleeping more than usual, any regression from things she used to be able to do, seizure activity etc.) and report anything right away to the doctor.
So that's the plan! It is a relief to have one in place and I'm looking forward to normal results from the urinalysis!