hi stephanie this happened twice to me, in the end i had them done with my gp to save making the 100 mile round trip for the 3rd lot, i was so annoyed. they said it was because the bloods were left too long b4 being processed and then the second time i came back low iron. i went to my GP, told her the sitaution, she put me on iron tablets and redid my bloods which was super efficient! yey to the NHS!! my surgeon didnt think my GP would do it but i was honest and said i had booked time off work, booked hotel and travel etc and i couldnt bear the thought of it being cancelled, she was fab x hope you get it sorted x