Skip to content

Magnesium, Serum 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 magnesium level helps assess your body’s mineral balance and overall health."]

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

Key facts at a glance

LOINC
17236-1
Short code
Magnesium Stl-sCnc
Synonyms
Magnesium Stl-sCnc
Category
electrolyte
Sample
stool
Container
Clean container
Units
N/A
Ref low
1.7
Ref high
2.2
Critical range
1 N/A – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83735
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Doctors may order a magnesium test to check for low or high levels, which can cause symptoms like muscle weakness, irregular heartbeat, or nerve problems. It’s also used to monitor conditions like kidney disease, heart rhythm disorders, or certain medications that affect magnesium levels.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw if your doctor specifies it. Wear comfortable clothing and plan to stay near the testing site for a short time.

How the Test Is Performed

A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight sting, but it’s usually over quickly. The blood sample is then sent to a lab for analysis.

Possible Results and Interpretation

Results are compared to standard reference ranges for healthy adults. Low magnesium levels may indicate deficiencies, while high levels could signal kidney problems or other health concerns. Your doctor will discuss your specific results with you.

Reference range

Adult: 1.7-2.2 mg/dLN/A

Specimen: stool

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Magnesium Level

Frequently asked questions

What causes low magnesium levels?
Low magnesium (hypomagnesemia) can result from poor diet (low intake of foods like nuts, leafy greens, or whole grains), kidney problems that prevent proper absorption, vomiting or diarrhea, excessive sweating, or certain medications (e.g., diuretics, antibiotics). Chronic alcohol use may also deplete magnesium over time.
What causes high magnesium levels?
High magnesium (hypermagnesemia) is less common but can occur with kidney failure (since the body can’t filter it out), excessive intake of magnesium supplements or antacids, or certain medical conditions like Addison’s disease. Rarely, it may result from overuse of magnesium-containing laxatives.
How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will contact you to discuss the findings once they’re ready.
  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