Skip to content

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 potential deficiencies or excesses that may affect muscle, nerve, or heart function."]

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

Key facts at a glance

LOINC
90848-3
Short code
MAG/SGPG IgM Titr CSF IA
Synonyms
MAG/SGPG IgM Titr CSF IA
Category
glucose
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test if you have symptoms like muscle cramps, weakness, irregular heartbeat, or conditions like low blood pressure, seizures, or certain metabolic disorders. It may also be part of routine checks for kidney disease or electrolyte imbalances.

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 instructed. Bring any medications you’re currently taking, as some can affect results.

How the Test Is Performed

A blood sample is drawn from a vein, typically in your arm, using a small needle. You may feel a slight pinch, but it usually doesn’t cause discomfort afterward.

What the Results Mean

Results are compared to standard reference ranges for your age and health status. Low levels may suggest deficiencies, while high levels could indicate kidney problems or other health concerns.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Magnesium

Frequently asked questions

What causes low magnesium levels?
Low magnesium (hypomagnesemia) can result from poor diet (low intake of nuts, leafy greens, or whole grains), chronic vomiting/diarrhea, kidney disease, or certain medications (e.g., diuretics, antibiotics).
What causes high magnesium levels?
High magnesium (hypermagnesemia) is less common but can occur with kidney failure (where the body can’t excrete excess magnesium), overuse of supplements, or certain medical conditions like Addison’s disease.
Can diet affect magnesium test results?
Yes, diet can influence results. High intake of magnesium-rich foods or supplements may temporarily raise levels. If you’re on a special diet (e.g., low-sodium), discuss it with your doctor to avoid misleading results.
  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