I should know the answer to this, as a seasoned asthmatic.... But actually now not 100% sure of the answer... I normally take my best peak flow as 350, as for the last couple of years this has where it has sat, however on looking at my medical records recently there have been a couple of occasions when it has been 460 (both readings on the new EU peak flow meter). So wondering if my best peak flow should be 460 rather than the 350. Obviously with a difference of 110 this would alter the points in my action plan considerably... Has anyone any thoughts on this???? I am erring on sticking on the 350 measurement which is what I take as my normal value.