Biomarker · Electrolytes
Magnesium
Magnesium is a mineral needed for muscles, nerves and heart rhythm. What a magnesium blood test shows and why a normal result does not always rule out low body stores.
Written by LON6EVITY Editorial Team · Last updated
Why magnesium matters
Magnesium is involved in muscle and nerve function, heart rhythm, blood sugar control and bone health.
When it is tested
MedlinePlus explains that the test may be ordered for symptoms such as muscle cramps, weakness or irregular heartbeat, or when potassium or calcium levels are abnormal, since low magnesium can make these hard to correct.
Limitations
Most magnesium is inside cells and bones, so a blood test reflects only a small part of the body's total. Kidney disease, alcohol use, some diuretics and proton pump inhibitors can affect levels.
Reference ranges
Reference ranges differ between laboratories, units and methods, and depend on age, sex and your overall clinical picture. A single result is not a diagnosis — interpret it with a qualified clinician.
Factors that can affect the result
- Diet
- Alcohol
- Diuretics
- Proton pump inhibitors
- Kidney function
- Diarrhoea
Questions people commonly ask
- Should I take magnesium supplements?
- Only after discussing it with a clinician, especially if you have kidney disease.
Related biomarkers
Related tests
Understand your biomarkers in context
What does this mean for your own health data? Log your results, follow trends over time and bring an organised summary to your next doctor's appointment.
Sources
- Magnesium Blood Test. MedlinePlus, U.S. National Library of Medicine.