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Magnesium blood test
Magnesium - blood
A serum magnesium test measures the level of magnesium in the blood.
How the Test is Performed
A blood sample is needed.
Blood sample
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
How to Prepare for the Test
No special preparation is needed.
How the Test will Feel
When the needle is inserted to draw blood, some people feel slight pain. Others feel a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
This test is done when your health care provider suspects you have an abnormal level of magnesium in your blood.
About half of the body's magnesium is found in bone. The other half is found inside cells of body tissues and organs.
Magnesium is needed for nearly all chemical processes in the body. It helps maintain normal muscle and nerve function, and keeps the bones strong. Magnesium is also needed for the heart to function normally and to help regulate blood pressure. Magnesium also helps the body control blood sugar level and helps support the body's defense (immune) system.
Normal Results
The normal range for blood magnesium level is 1.7 to 2.2 mg/dL.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.
What Abnormal Results Mean
A high magnesium level may indicate:
-
The adrenal glands are not producing enough hormones (
Addison disease
)
Addison disease
Addison disease is a disorder that occurs when the adrenal glands do not produce enough hormones.
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Loss of kidney function (
chronic renal failure
)
Chronic renal failure
Chronic kidney disease is the slow loss of kidney function over time. The main job of the kidneys is to remove wastes and excess water from the body...
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Loss of body fluids (
dehydration
)
Dehydration
Dehydration occurs when your body does not have as much water and fluids as it should. Dehydration can be mild, moderate, or severe, based on how muc...
ImageRead Article Now Book Mark Article - Diabetic ketoacidosis, a life-threatening problem in persons with diabetes
-
Producing less urine than usual (
oliguria
)
Oliguria
Decreased urine output means that you produce less urine than normal. Most adults make at least 500 ml of urine in 24 hours (a little over 2 cups)....
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A low magnesium level may indicate:
-
Alcoholism
or severe alcohol withdrawal (
delirium tremens
)
Alcoholism
Alcohol use disorder is when your drinking causes serious problems in your life, yet you keep drinking. You may also need more and more alcohol to f...
ImageRead Article Now Book Mark ArticleDelirium tremens
Delirium tremens is a severe form of alcohol withdrawal. It involves sudden and severe mental or nervous system changes.
Read Article Now Book Mark Article - Chronic (long-term) diarrhea
-
Treatment to remove waste from the blood (
hemodialysis
)
Hemodialysis
Artificial kidneys - hemodialysis; Dialysis; Renal replacement therapy - hemodialysis; End-stage renal disease - hemodialysis; Kidney failure - hemod...
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Scarring of the liver and loss of liver function (
cirrhosis
)
Cirrhosis
Cirrhosis is scarring of the liver and poor liver function. It is the last stage of chronic liver disease.
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Adrenal gland produces too much of the hormone aldosterone (
hyperaldosteronism
)
Hyperaldosteronism
Hyperaldosteronism is a disorder in which the adrenal gland releases too much of the hormone aldosterone into the blood. Hyperaldosteronism can be pr...
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Parathyroid glands do not produce enough parathyroid hormone (
hypoparathyroidism
)
Hypoparathyroidism
Hypoparathyroidism is a disorder in which the parathyroid glands in the neck do not produce enough parathyroid hormone (PTH).
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Inflammation of the pancreas (
pancreatitis
)
Pancreatitis
Acute pancreatitis is sudden swelling and inflammation of the pancreas.
ImageRead Article Now Book Mark Article - Too much insulin
-
High blood pressure and protein in the urine in a pregnant woman (
preeclampsia
)
Preeclampsia
Preeclampsia is when a pregnant woman develops high blood pressure and protein in the urine after the 20th week of pregnancy.
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Inflammation of the lining of the large intestine and rectum (
ulcerative colitis
)
Ulcerative colitis
Ulcerative colitis is a condition in which the lining of the large intestine (colon) and rectum become inflamed. It is a form of inflammatory bowel ...
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Risks
There is very little risk in having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
References
Klemm KM, Klein MJ. Biochemical markers of bone metabolism. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 15.
Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 218.
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
-
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
-
High blood pressure
(Alt. Medicine)
-
High blood pressure
(In-Depth)
-
Diabetes
(Alt. Medicine)
-
Stroke
(Alt. Medicine)
-
Atherosclerosis
(Alt. Medicine)
-
Myocardial infarction
(Alt. Medicine)
-
Hypoglycemia
(Alt. Medicine)
-
Sickle cell disease
(In-Depth)
-
Heart attack and acute coronary syndrome
(In-Depth)
-
Diabetes diet
(In-Depth)
Review Date: 1/31/2015
Reviewed By: Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
