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Comment by petilon

9 hours ago

Blood tests are pretty useless for magnesium. The deficiency is in cells, magnesium level in blood is not a good test for that deficiency.

They have blood tests for both (serum or RBC):

The Magnesium RBC Test measures magnesium inside red blood cells, providing a more accurate assessment of magnesium status than serum tests.

wouldn't a cell deficiency lead to it depleting also the magnesium levels in the blood, simply based on osmosis?

  • The organism dumps Mg on the blood as much as necessary because it needs to remain in stable concentrations.

    When a serum Mg test comes out low, the patient already has severe deficiency and visible symptoms, so isn’t very useful unless you’re investigating a systemic issue.

    As explained by my endocrinologist.