Red cell magnesium

Magnesium deficiency is particularly difficult to diagnose in mild cases, which almost always have few or no symptoms. Specific blood tests can be used, or a simple test that involves injecting magnesium into the patient and then monitoring its presence in the urine. The routine blood test used to detect magnesium usually measures its concentration in the blood. However, blood magnesium makes up only 1% of the total. To estimate the amount of magnesium inside cells, red blood cell magnesium is measured, i.e. the concentration of the mineral inside the red blood cells.