1. How to Cure a Magnesium Deficiency - http://www.livestrong.com/article/34141-cure-magnesium-deficiency/
“Although magnesium deficiency is rare, when it does occur it can cause symptoms such as fatigue, vertigo, muscle weakness, cardiac arrhythmia and involuntary muscle twitches or tremors. Magnesium deficiency is usually caused by malnutrition, kidney disease, uncontrolled diabetes, chronic alcoholism or malabsorption problems. Certain medications or removal of the parathyroid glands also can be responsible for this mineral deficiency. Magnesium deficiency is sometimes difficult to diagnose, but it can be treated once clinically confirmed.
3. Blood Levels
Testing magnesium levels to find if they are normal requires a simple blood draw. Levels are considered normal in the range of 1.7 to 2.2 mg/dL. Your doctor might choose to test your magnesium levels if you have tested low for potassium and calcium or if you have a history of kidney disease. Sometimes your body will released store magnesium from your bones to make up for a deficiency. In this situation, your blood test could read normal, but additional testing or symptoms may lead your doctor to find that your magnesium levels are in fact not normal.
4. When can magnesium deficiency occur? - http://ods.od.nih.gov/factsheets/magnesium
5. Hypomagnesemia - http://en.wikipedia.org/wiki/Hypomagnesemia