Magnesium (Mg)

Results

A magnesium test measures the level of magnesium in the blood. Normal values may vary from lab to lab. Results are usually available in 1 to 2 days.

Normal

Magnesium blood level

Adult:	1.3–2.1 milliequivalents per liter (mEq/L) or 0.65–1.05 millimoles per liter (mmol/L)
Child:	1.4–1.7 mEq/L or 0.7–0.85 mmol/L
Newborn:	1.4–2 mEq/L or 0.7–1.0 mmol/L

Many conditions can change magnesium levels.Your doctor will talk with you about any abnormal results that may be related to your symptoms and medical history.

High values

High magnesium levels may be caused by:

• Dehydration.
• Diseases of the adrenal glands, such as Addison's disease.
• An overactive parathyroid gland (hyperparathyroidism).
• An underactive thyroid gland (hypothyroidism).
• Kidney failure.
• Medicine that contains magnesium, such as antacids and laxatives.

Low values

Low magnesium levels may be caused by:

• Alcohol abuse or withdrawal.
• Complications from diabetes, such as diabetic ketoacidosis.
• Diseases that block with the way food is absorbed in the intestines, such as sprue.
• High blood calcium levels (hypercalcemia).
• Infection and swelling of the pancreas (pancreatitis).
• Kidney disease.
• Long-term diarrhea.
• Not getting enough magnesium in the foods you eat.
• Problems with pregnancy, such as toxemia of pregnancy (preeclampsia).
• Severe burns.
• Starvation or severe dieting.
• An overactive thyroid gland (hyperthyroidism).
• Underactive parathyroid glands (hypoparathyroidism).

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Author:	Maria G. Essig, MS, ELS	Last Updated: April 17, 2008
Medical Review:	Kathleen Romito, MD - Family Medicine Brian D. O'Brien, MD - Internal Medicine
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