Magnesium, Serum Concentration
This test measures the amount of magnesium in your blood serum, an important mineral that helps with muscle and nerve function, bone health, and many other body processes.
["Your magnesium level helps doctors check for deficiencies or excesses that could affect your health."]
Key facts at a glance
- LOINC
- 55938-5
- Short code
- Magnesium TPN-sCnc
- Synonyms
- Magnesium TPN-sCnc
- Category
- electrolyte
- Sample
- serum
- Container
- Red-top tube (SST)
- 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 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 This Test Might Be Ordered
Your doctor may order this test if you have symptoms like muscle weakness, cramps, irregular heartbeat, or numbness. It could also be done to monitor conditions like kidney disease, diabetes, or certain medications that affect magnesium levels.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for a few hours before the blood draw, but always follow your doctor’s instructions. Avoid taking magnesium supplements or certain medications for a day or two before testing.
How the Test Is Performed
A small needle will be used to draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.
What the Results Mean
Results are compared to a standard range for healthy adults. Low levels may indicate conditions like malnutrition, kidney problems, or certain medications. High levels could suggest kidney disease, excessive vitamin D, or overuse of magnesium supplements.
Reference range
Adult: 1.7-2.2 mg/dLN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Magnesium is vital for nerve and muscle function, blood pressure regulation, and energy production. Low levels can lead to weakness, heart rhythm issues, or seizures, while high levels may cause nausea, irregular heartbeat, or muscle spasms. Regular monitoring is important for patients with chronic conditions like diabetes or kidney disease.
Short name
Magnesium Level
Frequently asked questions
How long does it take to get my results?
Can I eat or drink before the test?
What if my results are outside the normal range?
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