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Magnesium, Serum Concentration (Mass Concentration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of magnesium, a mineral essential for many bodily functions, in your blood serum.

Quick summary

["Your doctor may check magnesium levels to monitor health or diagnose potential deficiencies or imbalances."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
111025-3
Short code
MAG IgM Msmt Ser
Synonyms
MAG IgM Msmt Ser
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you have symptoms like muscle cramps, weakness, or irregular heartbeat. It could also be part of routine check-ups, especially for those with kidney disease, heart conditions, or certain medications that affect magnesium levels.

What to Expect Before the Test

No special preparation is needed, but avoid drinking water or eating for a few hours before the blood draw. Wear comfortable clothing and arrange for someone to drive you home if needed.

What Happens During the Test?

A healthcare professional will insert a small needle into a vein in your arm to collect a blood sample. You may feel a slight pinch, but the process is quick and usually painless.

What Are Possible Results?

Results will be reviewed by your doctor to determine if your magnesium levels are within normal ranges or if further action is needed. They may compare your results to your baseline or other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Magnesium

Frequently asked questions

How often should I get this test?
The frequency depends entirely on your healthcare provider’s recommendations. They may suggest regular testing if you have conditions like kidney disease, diabetes, or are taking certain medications that affect magnesium levels.
What do my results mean if they are outside the normal range?
If your results are low, your doctor may recommend dietary changes, supplements, or further tests to identify the cause. If high, they may adjust medications or treatments to bring levels back into balance.
Can diet affect magnesium test results?
Yes, your diet can influence magnesium levels. Eating foods rich in magnesium (like nuts, leafy greens, and whole grains) or avoiding excessive alcohol and caffeine may help stabilize results. Avoiding magnesium-containing supplements before testing can also help ensure accurate results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy