Magnesium Most Popular

The Magnesium test contains 1 test with 1 biomarker.

Description: A Magnesium test is a blood test that measures magnesium levels in your blood’s serum and is useful in determining the cause of abnormal levels of magnesium, calcium, and or potassium, and is useful in the evaluation of a wide variety of disorders such as diabetes, kidney disease, and malabsorption.

Also Known As: Magnesium Serum Test, Mg Test, Mag Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

Average Processing Time: 1 to 2 days

When is a Magnesium test ordered?

Magnesium tests may be requested by health professionals as a follow-up to chronically low calcium and potassium levels in the blood. It may also be ordered if a person is experiencing muscle weakness, cramping, twitching, disorientation, seizures, or cardiac arrhythmias, which could be caused by a magnesium deficit.

As part of an evaluation of malabsorption, malnutrition, diarrhea, or alcoholism, a health practitioner may prescribe a magnesium level to check for a deficit. Testing may also be done if someone is taking drugs that cause the kidneys to excrete magnesium. When magnesium and/or calcium supplementation is required, the level of magnesium in the blood can be measured at regular intervals to ensure that the medication is working.

A magnesium test, along with kidney function tests such as a BUN and creatinine, may be given on a regular basis when someone has a kidney problem or uncontrolled diabetes to help monitor renal function and ensure that the person is not excreting or retaining excessive quantities of magnesium.

What does a Magnesium Serum test check for?

The magnesium test measures the amount of magnesium in your blood’s serum. Magnesium is a mineral that supports healthy bones, neuron function, muscle contraction and energy production. It enters the body through the diet and is then processed by the small intestine and colon. Tissues, cells, and bones all contain the element magnesium. It is challenging to determine the total magnesium content from blood tests alone since only 1% of the magnesium present in the body is accessible in the blood. However, this test is still useful for figuring out a person's magnesium levels.

Small levels of magnesium can be found in a range of meals, including green vegetables like spinach, whole grains, and nuts. Magnesium is commonly found in foods that contain dietary fiber. The body regulates how much magnesium it receives and excretes or conserves in the kidneys to keep its magnesium level stable.

Magnesium deficiency can occur as a result of malnutrition, malabsorption-related disorders, or excessive magnesium loss via the kidneys. Magnesium overload can occur as a result of taking magnesium-containing antacids or a decrease in the kidneys' ability to eliminate magnesium.

There may be no or few nonspecific symptoms in someone with mild to severe magnesium insufficiency. Loss of appetite, nausea, muscle cramps, confusion, exhaustion, seizures, changes in heart rate, and tingling or numbness are all symptoms of persistent or severe deficits. They can also wreak havoc on calcium metabolism and worsen calcium deficiency. Muscle weakness, nausea, loss of hunger or cravings, and an erratic heart rate are some of the symptoms of excess magnesium, which are similar to those of deficiency.

Lab tests often ordered with a Magnesium test:

  • Complete Blood Count
  • Calcium
  • Iron Total and Total Iron binding capacity
  • Potassium
  • Comprehensive Metabolic Panel
  • Lipid Panel
  • Phosphorus
  • Parathyroid Hormone
  • Vitamin D
  • Glucose

Conditions where a Magnesium test is recommended:

  • Hypomagnesemia
  • Hypermagnesemia
  • Kidney Disease
  • Hypothyroidism
  • Diabetes
  • Alcoholism
  • Malnutrition
  • Malabsorption
  • Diarrhea
  • Dehydration
  • Parathyroid Diseases
  • Addison Disease
  • Adrenal Insufficiency

How does my health care provider use a Magnesium test?

Magnesium levels in the blood are measured with a magnesium test. Atypical magnesium levels are most frequently found in conditions or illnesses that result in insufficient or excessive renal excretion of magnesium or impaired intestinal absorption of magnesium. Magnesium levels can be measured to determine the severity of kidney issues, uncontrolled diabetes, as well as to diagnose gastrointestinal diseases.

Because a low magnesium blood level can lead to chronically low calcium and potassium levels over time, it may be tested to help diagnose calcium, phosphorus, potassium, and/or parathyroid hormone – another component of calcium regulation – problems.

Magnesium levels can be checked on a regular basis to monitor the response to oral or intravenous magnesium supplements, and calcium supplementation can be monitored using calcium and phosphorus tests.

What does my Magnesium test result mean?

Low magnesium levels in the blood can suggest that a person isn't getting enough magnesium or is excreting too much. Deficiencies are most commonly encountered in:

  • Low nutritional intake 
  • Gastrointestinal conditions
  • Diabetes that is uncontrolled
  • Hypoparathyroidism
  • Use of a diuretic for a long time
  • diarrhea that lasts for a long time
  • Following surgery
  • Burns that are severe
  • Pregnancy toxicity

Magnesium levels in the blood are rarely elevated as a result of food sources, but rather as a result of an excretion problem or excessive supplementation. Increased levels can be cause by:

  • Failure of the kidneys
  • Hyperparathyroidism
  • Hypothyroidism
  • Dehydration
  • Diabetic acidosis
  • Addison's disese
  • Use of antacids or laxatives containing magnesium

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.


*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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