Can anyone please tell me in what way the ranges affect the results? The reason I ask this is, do they re-calibrate their test equipment or something? Does that mean, for example, the same specimen could come up 0.5 in one lab and 1.0 in another? I had the vague idea that your own level would be absolute (give or take a margin for error). I live in a village with mainly older people in it - a fair number are under-active I think, or so it seems from talking to people. Would that skew the results? And if so, would sending to Blue Horizon, for example, give me a more realistic result? Suddenly it all seems to be a minefield!