Magnesium Blood Test: What to Know
This blood test can detect magnesium deficiency or levels that are too high
Medically reviewed by Karina Tolentino, RD, CHWC
Magnesium is a mineral found both in the earth and in your body. It’s required for healthy bones, muscles, hearts, and nerves, allowing your body to control energy, blood sugar, blood pressure, and many other processes. People consume magnesium through many common foods, including nuts, whole grains, and leafy greens. If your healthcare provider suspects you have a magnesium deficiency (low magnesium) or that your levels are too high, they’ll order a magnesium blood test to measure magnesium levels in your body.
This article explains what a magnesium blood test is, what normal magnesium levels are, and what a magnesium normal range looks like. It also covers magnesium deficiency symptoms, low magnesium causes, and how to tell if your magnesium levels are high.
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What Is a Magnesium Blood Test?
A magnesium blood test measures the amount of magnesium in your blood. In addition to blood, magnesium is found in your bones and cells, but the amount in your blood can help healthcare providers understand if your magnesium levels are too low or too high.
A magnesium blood test is the same as other common blood tests. During the test, a nurse or healthcare worker will collect a sample of your blood. They usually do this from a vein in your arm. The blood then runs through a tube into a vial that then goes to the lab for analysis.
Who Needs a Magnesium Blood Test?
Your healthcare provider will order a magnesium blood test if they believe your magnesium levels might be too high or too low. Symptoms like muscle weakness or irregular heartbeat can indicate either high or low magnesium, and if you have those symptoms, your healthcare provider may order a magnesium blood test.
Sometimes, pregnant people need a magnesium blood test, too. Magnesium deficiency can be a sign of preeclampsia, a rare high blood pressure condition in pregnant people.
How to Tell if You Have Low Magnesium
If you have low magnesium levels (which is also known as hypomagnesemia), you’ll start noticing symptoms that may include muscle weakness, cramps, twitching, and an irregular heartbeat. The symptoms can get worse over time.
Magnesium deficiency is rare in otherwise healthy people. However, low magnesium is more common in older adults, people on medications, and people with certain conditions, including:
Low Magnesium Symptoms
The symptoms of low magnesium levels include:
Muscle weakness
Muscle cramps
Loss of appetite
Nausea and vomiting
Confusion
Irregular heartbeat
Magnesium Deficiency Symptoms
If your magnesium levels stay low and you become deficient (meaning your body doesn’t have enough magnesium to stay healthy) you’ll notice more severe symptoms, including:
Numbness in your hands and feet
Abnormal heart rhythms (arrhythmia)
Abnormal eye movements (nystagmus)
Changes in personality or behavior
Seizures
Coma
Low magnesium is also linked to the start of other serious health conditions including:
How to Tell if Your Magnesium Levels Are High
High magnesium levels, known as hypermagnesemia, are rare. That’s because in healthy individuals, the kidneys excrete any extra magnesium that your body doesn’t need. However, hypermagnesemia can happen in people who have kidney failure or chronic kidney disease.
The symptoms of high magnesium levels include:
Muscle weakness
Fatigue
Nausea and vomiting
Trouble breathing
Cardiac arrest
How to Prepare for a Magnesium Blood Test
Your healthcare provider will tell you whether you need to fast (not eat or drink) before the test. Fasting isn’t typically required for a magnesium blood test, but if you’re taking other tests at the same time, they might require this.
Other than that, there is nothing special you need to do for the blood test.
What Happens During a Magnesium Blood Test
During the blood test, a healthcare provider will draw blood from a vein in your arm. After they insert the needle and collect the blood, they will send it to a lab for analysis.
Getting Your Magnesium Blood Test Results
Within a few days, you’ll be able to see your magnesium blood test results online or call your healthcare provider to get the results. Typically, the normal magnesium range is 1.7 to 2.2 milligrams per deciliter. However, the range for normal can vary from one lab to another, so always ask your healthcare provider if your range is normal.
If your results are above or below that, your healthcare provider will explain what that might mean. Treatments for low magnesium can include oral magnesium supplements, magnesium infusions, and dietary changes. Whether your results are high or low, your healthcare provider may want to address any possible underlying health conditions, such as kidney disease.
Are There Any Risks to the Test?
Magnesium blood tests are generally safe. However, you might experience some pain when the healthcare provider inserts a needle or removes it from your arm. If you have any anxiety about blood, discuss this with your healthcare provider.
Summary
A magnesium blood test measures the magnesium in your blood. It can help diagnose high or low magnesium levels and sometimes also help diagnose preeclampsia, a high blood pressure condition that impacts pregnant people.
A magnesium blood test is a straightforward blood draw, requiring no special preparation. Typically, the normal range for adults is 1.7 to 2.2 milligrams per deciliter, but your lab may have different ranges than others do, so it’s best to ask your healthcare provider whether your levels are normal. If they’re not, your healthcare provider will work with you to stabilize your levels and address any underlying health conditions that might factor into this.
Read the original article on Verywell Health.
