Chris
Your take on this is pretty right. It is what it is, and at your age the chances of organ damage are slim. I am impressed that your GP seems to have nailed it that fast.
Next step will probably be a gastroenterologist to give the liver & panceas the once over. Your GP will sort that for you I'd have thought.
Wait for the confirmation with the gene test. It still could be something else.
As for the blood bank... never hurts. For the record, the GP might send you to pathology for venesection... Blood bank is a better & friendlier option, they just wont do analysis of blood. You need a seperate pathology test regularly to sort that. When you get that far you can get the referal forms from this link.
http://www.manual.transfusion.com.au/Transfusion-Clinical-Practice/Therapeutic-Venesection.aspxGood luck and keep in touch. You will need lots of thought clarification on this subject if you are affected. You will need to understand and manage it yourself, don't leave your trust in the medicos.
StaveF