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Serum Magnesium 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

["Magnesium helps with muscle and nerve function and keeps your heart rhythm steady."]

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

Key facts at a glance

LOINC
23907-9
Short code
MAG/SGPG IgM Ser-aCnc
Synonyms
MAG/SGPG IgM Ser-aCnc
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 This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like muscle cramps, weakness, or irregular heartbeat, or if you have conditions such as kidney disease, diabetes, or certain medications that affect magnesium levels. It may also be part of routine monitoring for patients with chronic illnesses or those receiving intravenous fluids.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves a blood draw. Avoid alcohol and certain supplements (like magnesium-containing products) for 24 hours prior.

How the Test Is Performed

A blood sample is taken from a vein, usually in your arm, using a small needle. The sample is then sent to a lab for analysis.

Possible Results and Interpretation

Results are compared to standard reference ranges, but your doctor will discuss your specific results in the context of your health. Low or high levels can indicate underlying health concerns that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low magnesium levels (hypomagnesemia) may cause muscle spasms, seizures, irregular heartbeat, or weakened bones. High magnesium levels (hypermagnesemia) can lead to nausea, confusion, or slowed heart rate. Both extremes can affect other body systems and may require medical attention or treatment adjustments.

Short name

Magnesium Level

Frequently asked questions

What causes low magnesium levels?
Conditions like kidney disease, vomiting/diarrhea, poor diet, or certain medications (e.g., diuretics) can deplete magnesium. Chronic alcohol use or malabsorption disorders may also contribute.
What causes high magnesium levels?
Kidney failure, excessive magnesium supplements, or certain medications (e.g., laxatives with magnesium) can raise magnesium levels. Rarely, overactive parathyroid glands or adrenal insufficiency may play a role.
Can I adjust my diet to manage magnesium levels?
Dietary changes alone won’t replace medical treatment, but foods rich in magnesium (leafy greens, nuts, seeds, whole grains) may help if levels are slightly low. Always consult your doctor before making changes.
  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