Magnesium and Human Health: Perspectives and Research Directions

Table 3

Assessment of magnesium status.

Test	Comments
Serum magnesium	Sometimes not adequate since less than 0.3% of total body magnesium is found in serum. However, it is easy, accessible, and cheap.
24 hours excretion in urine or the fractional excretion of magnesium	Helps in differentiating renal wasting of magnesium from inadequate intake or poor absorption as an etiology for hypomagnesemia.
Magnesium loading test	Identifies patients with normomagnesic magnesium deficiency.
	Assesses intestinal absorption of magnesium.
	Indirectly assesses bone status of magnesium.
Magnesium concentration in RBCs	Can give early indication of magnesium deficiency.
Isotopic analysis of magnesium	Assesses the absorption of magnesium from the gastrointestinal tract in research setting.
Ionized magnesium	More accurate, especially in critically ill patients with rapid change in hemodynamics.
	Not effected by low albumin.

RBCs: red blood cell counts.