A patient seated in the chair before a blood draw
In person

Magnesium

Your blood magnesium level, a key mineral, from one blood draw.

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  • 2,000+ lab locations. Find one near you
  • Nothing due at the lab. FSA / HSA accepted
  • Ordered by a licensed clinician

At a glance

Collection
Blood draw
A standard blood draw at the lab.
Preparation
None
Nothing to do ahead of time. Water is fine.
Results
1 to 2 days
Typical turnaround after your visit.
Where
2,000+ lab locations
Nationwide, with nothing due at the lab.

About this test

Magnesium is a mineral your body uses for muscle and nerve function, heart rhythm, and many other processes. Most of it is stored in bone and inside cells, so blood holds a small share of the total, and a result is read with other results. Standard metabolic panels do not include it.

For adults 18 and older. Test availability varies by lab location.

Who should take this test?

This test is often used by adults with muscle cramps or twitches, palpitations, or ongoing tiredness, or who are following up on a past magnesium result. Commonly related symptoms include:

Body

  • Muscle cramps
  • Muscle twitches
  • Tiredness

Heart

  • Palpitations

Stomach

  • Nausea
  • Loss of appetite

Ask about this test

Not sure this is the right test?

AI-generated. For information only, not medical advice. Call 911 for an emergency.

What does this test measure?

Your result shows how much magnesium is in your blood, which a healthcare provider can read with your kidney function, other minerals, and your symptoms.

Magnesium
Magnesium is a mineral involved in muscle and nerve function, heart rhythm, and many of your body’s chemical reactions. Most of it is stored in bone and cells, so the blood level is only a small part of your total. It can be affected by diet, absorption, kidney function, and some medicines.
Why it’s measured: To check a mineral involved in muscle, nerve, and heart function.

How it works

  1. Step 1

    Order online

    Check out here. A licensed clinician in your state reviews your order and sends it to the lab.

  2. Step 2

    Visit a lab

    Bring a photo ID to any of 2,000+ lab locations. No fasting needed, and nothing is due at the lab.

  3. Step 3

    Get your results

    Results post to your account, usually in 1 to 2 days, each number next to the lab’s reference range.

Find a lab near you

Choose from 2,000+ lab locations nationwide. Your order works at any of them.

What your results tell you

Magnesium is reported in milligrams per deciliter (mg/dL) and compared with the lab’s reference range. It reflects blood, not total body stores.

  • Your number next to the lab’s reference range
  • Explained in plain language
  • A licensed clinician reviews your order and, if appropriate, orders the test.
  • A lab report you can download and share

A healthcare provider reads magnesium with kidney function and other results, and decides whether a repeat or added test is needed.

Clinical-grade testing, from the comfort of home.

From the lab to your report, every step of our process meets the gold standard in medical testing.

  • CLIA-certified labs

    Every lab we partner with is certified under the Clinical Laboratory Improvement Amendments, meeting both state and federal standards with regular independent inspections.

  • We protect your health data

    We protect your health data with encryption and do not sell it. Some results must be reported to public health authorities by law. See our Privacy Notice.

  • Rigorous quality assurance

    All partner labs run regular internal quality checks, participate in proficiency testing, and comply with federal and state lab regulations.

  • Clinician-reviewed reports

    Results are reviewed by an independent, licensed clinician.

Questions

Common questions.

Anything else, our care team answers by phone, text, or email.

No. Most of your body’s magnesium is stored in bone and inside cells, and blood carries a small share of the total. Your body works to keep the blood level steady, so a result within the range may not reflect your stores.

That is why a healthcare provider reads magnesium with your symptoms and other results.

Your kidneys help control how much magnesium your body keeps, so kidney function matters. The lab notes that magnesium can be lower with some kidney and digestive conditions and with alcohol-⁠related liver disease, and higher when the kidneys are not working well.

A healthcare provider can look for a cause if your result is outside the range.

A result outside the range is a prompt to talk with a healthcare provider. They may repeat the test, check kidney function and other minerals, or look at your medicines and diet before deciding on next steps. Follow up promptly if you also have palpitations or muscle weakness.

If palpitations come with chest pain, fainting, or trouble breathing, get emergency care right away.

Lab tests are informational and don’t diagnose conditions on their own. Available to adults 18 and older; test availability varies by lab location. A licensed clinician reviews your order and, if appropriate, orders the test. All testing is performed at CLIA-certified laboratories. Not for emergencies: if you think you may be having a medical emergency, call 911.