I can tell you exactly what to do. Get your doctor to give you a script, its called an ongoing script I think. You can then go in to any pathology to have the test and they will ring you on your mobile with the results and tell you what dosage to take till the next test.
Always keep hat script on you and use as you travel along.
My son who had the truck accident is on it and has done that between Vic and Qld for the last couple of years. Not sure how long the ongoing script lasts but can be renewed with your next doctor when you get to WA.