Blood test for magnesium

Answered on August 19, 2014
Created August 10, 2012 at 1:48 PM

Should a magnesium blood test be done on an empty stomach?

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3 Answers


on August 10, 2012
at 06:49 PM

A blood test for magnesium is mostly worthless. If it comes back, High, you probably have kidney issues. If it comes back , Low, you may or may not be magnesium deficient. The only test for magnesium that is accurate is called, Metabolic Balance. They give you an I.V load and then collect a 24 hour urine. If you retain more than 25% of the load then you are determined to be deficient.



on August 10, 2012
at 02:21 PM

There is no reliable blood test for magnesium since the body's reservoir for magnesium is not the blood; rather it is the bone. If you're blood level is our of range, it means something is out of wack but does not necessarily have implications regarding your magnesium intake.


on August 10, 2012
at 02:13 PM

You mean fasted? I'm not aware of any requirement. Also I'm unsure where erum magnesium testing is all that useful? - the body strives to keep blood levels at the 'right level' and only a very small fraction of Mg is in the bloodstream anyway (most is in the tissues). I had a hair mineral test done once, although I'm unsure of teh reliability of thsoe too...

Sorry, this doesn't really seem like a helpful answer in the end...

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