Blood tests: They don’t always tell you what’s going on in the part of the body where the symptoms are

Dr Hans Duvefelt

You would think simple atomic particles such as sodium, magnesium and iron would be evenly distributed throughout the body, and that their blood levels would tell us whether we have enough of them in our bodies.

I already knew that this was not the case with sodium or magnesium, but I recently learnt that the same situation exists with iron.