Magnesium, Serum or Plasma Concentration
This test measures the amount of magnesium, a mineral essential for many bodily functions, in your blood.
["Magnesium helps with muscle and nerve function, blood pressure, and bone health."]
Key facts at a glance
- LOINC
- 35249-2
- Short code
- Magnesium SerPl-msCnc
- Synonyms
- Magnesium SerPl-msCnc
- 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 Might You Need This Test?
Your healthcare provider may order this test if you have symptoms like muscle weakness, cramps, irregular heartbeat, or signs of low or high magnesium levels. It may also be checked during certain medical conditions, such as kidney disease, heart problems, or electrolyte imbalances.
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. Wear comfortable clothing and plan to rest after the test.
What the Test Results Mean
Results are compared to standard ranges, but individual ranges can vary. Low magnesium levels may cause muscle spasms or irregular heartbeat, while very high levels can lead to nausea, confusion, or abnormal heart rhythms.
Common Reasons for Testing
Doctors often check magnesium levels to diagnose or monitor conditions like hypomagnesemia (low magnesium), hypermagnesemia (high magnesium), or to assess kidney function and electrolyte balance.
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.
Clinical Significance: Magnesium plays a critical role in nerve and muscle function, blood pressure regulation, and bone health. Abnormal levels can affect heart rhythm, muscle contractions, and even mood. Regular monitoring is important for patients with chronic conditions like kidney disease or those taking certain medications that may alter magnesium levels.
Short name
Magnesium Level
Frequently asked questions
How long does it take to get my test results?
Can I eat or drink before the test?
What are the normal ranges for magnesium?
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