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Serum Magnesium 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, blood pressure, and energy production."]

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

Key facts at a glance

LOINC
95180-6
Short code
M gallisep Ab Titr Ser IA
Synonyms
M gallisep Ab Titr Ser IA
Category
coagulation
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 doctor may order this test to check for low or high magnesium levels, which can affect heart rhythm, muscle weakness, or other health issues. It may also be done if you have symptoms like muscle cramps, fatigue, or irregular heartbeat, or if you’re taking certain medications that affect magnesium levels.

What to Expect During the Test

A blood sample is taken from a vein, usually in your arm. You may feel a slight pinch, but it’s quick and doesn’t require special preparation. The sample is sent to a lab for analysis.

Common Reasons for Testing

This test is often done to diagnose or monitor conditions like hypomagnesemia (low magnesium), hypermagnesemia (high magnesium), or to check for electrolyte imbalances. It may also be part of routine blood work or if you’re undergoing treatment for conditions like kidney disease or heart problems.

How Results Are Interpreted

Results are compared to a standard range, though exact values can vary by lab. Low levels may indicate health risks, while high levels could also signal problems. Your doctor will discuss findings with you based on your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Magnesium Level

Frequently asked questions

What causes might lead to abnormal magnesium levels?
Magnesium levels can be affected by diet, kidney function, certain medications, or medical conditions like diabetes or heart disease. Symptoms of imbalance may include muscle spasms, numbness, or irregular heartbeat. If you notice these or other concerning signs, talk to your doctor.
How can I prepare for this test?
No special preparation is needed, but avoid eating or drinking anything (except water) for a few hours before the test if instructed. Wear comfortable clothing and let your doctor know about any medications you’re taking.
Will the results affect my treatment?
Yes, your doctor may adjust medications, treatments, or lifestyle changes based on the results. Follow-up tests or additional checks might be recommended if levels are out of range.
  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