Magnesium, Serum Concentration
This test measures the amount of magnesium, a mineral essential for many bodily functions, in your blood serum.
["Magnesium levels help assess your body’s mineral balance and overall health."]
Key facts at a glance
- LOINC
- 17311-2
- Short code
- MAG IgA Ser-aCnc
- Synonyms
- MAG IgA Ser-aCnc
- Category
- glucose
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82784
- 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 Is This Test Done?
Your doctor may order a serum magnesium test to check for low or high levels, which can affect muscle function, nerve signals, and heart health. It’s often done if you have symptoms like muscle weakness, cramps, or irregular heartbeat, or if you have conditions like kidney disease, diabetes, 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 8–12 hours before the test if instructed by your healthcare provider. Bring any medications you’re currently taking, as some can influence results.
During the Test
A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick and typically painless. The blood sample is then sent to a lab for analysis.
What the Results Mean
Results are compared to standard reference ranges, but exact values can vary by lab. Low magnesium may cause muscle spasms or weakness, while very high levels can lead to confusion, irregular heartbeat, or seizures. Your doctor will interpret results in the context of your overall health and symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Serum magnesium levels are critical for nerve and muscle function, blood pressure regulation, and bone health. Abnormalities can signal underlying conditions like malnutrition, kidney disorders, or metabolic imbalances. Chronic low levels may also worsen symptoms of diabetes or heart disease, while toxic levels can be life-threatening and require immediate medical attention.
Short name
Serum Magnesium
Frequently asked questions
How long does it take to get my results?
Can I eat or drink before the test?
What should I do if I have symptoms like muscle twitching or irregular heartbeat?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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