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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 levels help assess overall mineral balance and potential deficiencies or excesses."]

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

Key facts at a glance

LOINC
23250-4
Short code
M agalactiae Ab Ser Ql IA
Synonyms
M agalactiae Ab Ser Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like muscle weakness, cramps, or irregular heartbeat, or if you have conditions like kidney disease, diabetes, or certain medications that affect magnesium levels.

What Does the Test Involve?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it is analyzed to determine the magnesium concentration.

What Are Common Reasons for Testing?

Common reasons include diagnosing or monitoring magnesium deficiency or toxicity, checking electrolyte balance, and evaluating conditions like hypomagnesemia (low magnesium) or hypermagnesemia (high magnesium).

What Do Results Typically Mean?

Results help identify whether your magnesium levels are within normal range, low, or high. Abnormal levels may require further medical evaluation and treatment.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Magnesium plays a critical role in nerve and muscle function, blood pressure regulation, and maintaining healthy bones. Low levels can lead to muscle spasms, seizures, or irregular heart rhythms, while high levels may cause weakness, nausea, or slowed heart rate. Regular monitoring is important for patients with chronic conditions or those on certain medications that affect magnesium metabolism.

Short name

Serum Magnesium

Frequently asked questions

What causes low magnesium levels?
Low magnesium levels can result from poor diet, certain medications, chronic diarrhea, vomiting, excessive sweating, or kidney problems that don’t properly filter magnesium from the blood.
What are the symptoms of abnormal magnesium levels?
Symptoms of low magnesium include muscle twitches, cramps, spasms, weakness, numbness, irregular heartbeat, or seizures. Symptoms of high magnesium may include nausea, vomiting, low blood pressure, irregular heartbeat, or muscle weakness.
How often should I get this test?
The frequency depends on your health condition and medical needs. Your healthcare provider will determine how often to check your magnesium levels based on your specific situation.
  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