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Magnesium, Serum Concentration

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of magnesium in your blood serum, which helps assess your body’s mineral balance and overall health.

Quick summary

["Magnesium is essential for nerve function, muscle contractions, and bone health."]

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

Key facts at a glance

LOINC
111386-9
Short code
Magnesium Msmt Stl
Synonyms
Magnesium Msmt Stl
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 This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like muscle cramps, weakness, irregular heartbeat, or signs of electrolyte imbalances. It’s also used to monitor conditions like hypomagnesemia (low magnesium) or hypermagnesemia (high magnesium), or to check for kidney function or certain metabolic disorders.

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’s part of a broader metabolic panel. Wear comfortable clothing for blood draws.

What the Test Results Mean

Results are compared to standard reference ranges for your age and health status. Low levels may indicate dehydration, kidney disease, or certain medications, while high levels could suggest kidney problems or overuse of magnesium supplements.

Common Reasons for Abnormal Results

Low magnesium levels might cause fatigue, muscle spasms, or irregular heart rhythms. High levels could lead to nausea, low blood pressure, or confusion. Your provider will discuss these findings with you in detail.

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.

Clinical Significance: Role in Health and Disease

Short name

Magnesium Level

Frequently asked questions

What causes magnesium levels to be too low?
Low magnesium can result from poor diet (low intake of foods like nuts, leafy greens, or whole grains), certain medications (like diuretics or antibiotics), chronic kidney disease, or excessive vomiting/diarrhea. It may also be inherited in some cases.
What causes magnesium levels to be too high?
High magnesium levels are less common but can occur with kidney failure (which can’t remove excess magnesium), overuse of magnesium supplements, or certain medications. Rarely, it may be genetic.
How does magnesium relate to other health conditions?
Magnesium is linked to heart health, blood pressure, and muscle function. Low levels have been associated with hypertension, diabetes, and osteoporosis, while high levels may affect nerve signaling or heart rhythm. Always discuss results with your provider.
  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