I went to have a routine blood test this morning as part of my pre-op checks (knee replacement in September) and the nurse told me my blood group card was out of date (excuse me - my blood group hasn't changed LOL). ANd not only that but for the card now I have to have TWO tests, several hours apart (my group still doesn't change!). So instead of one test for the op she took extra blood for the card analysis and then I went back two hours later for the second one. So I have blue marks on both arms. I guess it is is a practise for the post-op checks - last time I remember having blood taken twice a day for the five days I was in hospital as part of anti-clotting checks. By the end, they couldn't find a vein.