Skip to content

Serum or plasma 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.

Quick summary

["Magnesium helps with muscle and nerve function, bone health, and energy production."]

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

Key facts at a glance

LOINC
91545-4
Short code
MOG Ab Ser Ql CBA IFA
Synonyms
MOG Ab Ser Ql CBA IFA
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
cba-ifa
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 if you have symptoms like muscle weakness, cramps, irregular heartbeat, or signs of low or high magnesium levels. It may also be done to monitor conditions like kidney disease, heart problems, or certain medications that affect magnesium balance.

What to Expect During the Test

A blood sample is taken from a vein, usually in your arm. You may feel a small pinch, but it shouldn’t cause significant discomfort. The test is quick and doesn’t require special preparation.

Common Reasons for Testing

Doctors check magnesium levels to diagnose or monitor conditions like hypomagnesemia (low magnesium) or hypermagnesemia (high magnesium), evaluate electrolyte imbalances, or assess responses to treatments.

What the Results Mean

Results help your healthcare provider determine if your magnesium levels are within the normal range or if further action is needed, such as dietary adjustments or medication.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Magnesium Level

Frequently asked questions

What causes magnesium levels to be too low or too high?
Low magnesium levels (hypomagnesemia) can result from poor diet, kidney problems, vomiting, diarrhea, or certain medications. High levels (hypermagnesemia) are less common but may occur with kidney failure, excessive magnesium supplements, or certain medications.
How often should I get this test?
Your doctor will determine how often to check your magnesium levels based on your health condition, symptoms, and treatment plan. Regular monitoring may be needed if you have chronic health issues like kidney disease or heart problems.
Can lifestyle changes affect magnesium levels?
Yes, diet plays a key role. Foods rich in magnesium include leafy greens, nuts, seeds, whole grains, and legumes. Avoiding excessive alcohol and managing stress can also help maintain balanced magnesium levels.
  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