Magnesium Test
A blood test that measures magnesium, needed for muscles, nerves and heart rhythm.
Quick Summary
To check magnesium in people with muscle cramps, irregular heartbeat, diarrhoea or long-term acid-reducer use.
Magnesium level.
No special preparation.
Overview
Low magnesium often comes with low potassium and calcium.
Long-term proton pump inhibitor use can lower magnesium.
What It Measures
Magnesium
Blood level.
How It's Performed
- 01
Preparation
Usually no special preparation. Tell the staff about medicines you take.
- 02
Blood sample
A small amount of blood is taken from a vein in your arm with a thin needle.
- 03
Afterwards
Press on the spot for a minute. A small bruise is common; you can go back to normal activities.
Reference Ranges
Note: Normal ranges vary by laboratory. Consult your report for the specific reference used.
| Parameter | Typical Range (Adult) | Units |
|---|---|---|
| Magnesium | 1.7–2.2 | mg/dL |
Interpreting Results & Next Steps
Discuss with Doctor
Normal ranges differ between laboratories, ages and sexes; always use the range printed on your report and ask your doctor what your results mean.
If values are Low:
Low magnesium can cause cramps, tremor and heart rhythm problems.
If values are High:
High magnesium is rare and usually linked to kidney failure or supplements.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Magnesium Blood Test(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Magnesium test(opens in a new tab) · NHS