Synonyms:  Mg, RBC

Why It Is Done

• Determine amount of magnesium within red blood cells

Test Overview

One can measure inter-cellular magnesium (in the serum), and find out how much Mg or any other

vitamin/mineral is in circulation.

This does not necessarily correlate with how much is in the actual cell/tissue.

When measuring Mg in the RBC, you are measuring

intracellular Mg, how much is in the cell and functioning.

How To Prepare

Do not take medications containing magnesium for at least 3 days before this test.

This includes antacids that contain magnesium,

certain laxatives (such as milk of magnesia or Epsom salts), magnesium supplements, and certain diuretics.