BLOOD TEST · SMART CARE POLYCLINIC, DEIRA
Magnesium explained
A mineral involved in muscle, nerve and heart function, often low without obvious symptoms.
What the Magnesium test measures
Used in hundreds of the body's chemical reactions, particularly muscle and nerve function and the heart's electrical rhythm. Most of it sits inside cells and in bone, with only a small fraction in blood — so a blood level can look normal while stores are low, which is the main limitation of the test.1
What the result tells you
If it's low
Muscle cramps, twitching, weakness and fatigue. When very low it disturbs heart rhythm.
It blocks other corrections
Calcium and potassium will not come back up while magnesium is low — a common reason a stubborn low potassium is not resolving.
A normal result is not proof
Most magnesium is inside cells, so blood can read normal while the body's total is not. It is read with the symptoms and the rest of the panel.
How to prepare
- Fasting
- Not needed
- Best time
- Any time, usually with the rest of the panel
- Worth knowing
- Tell the nurse if you take magnesium supplements.
What can move the result
A result outside the usual range does not on its own mean something is wrong. These are the everyday explanations a doctor considers first.
Packages that include it
Frequently asked questions
Used in hundreds of the body's chemical reactions, particularly muscle and nerve function and the heart's electrical rhythm. Most of it sits inside cells and in bone, with only a small fraction in blood — so a blood level can look normal while stores are low, which is the main limitation of the test. If it's low: Muscle cramps, twitching, weakness and fatigue. When very low it disturbs heart rhythm.
Fasting: Not needed. Best time: Any time, usually with the rest of the panel. Tell the nurse if you take magnesium supplements.
Commonly: alcohol use; long-term acid-reducing medicines; water tablets; prolonged diarrhoea or vomiting; poorly controlled diabetes. A single result is not a diagnosis. Values are read against the laboratory's own reference range and alongside your history, your symptoms and the rest of the panel — which is why every package includes a doctor to go through them with you.
At Smart Care Polyclinic, 29 Doha Centre, Al Maktoum Rd, Deira, Dubai. It is included in the Smart Extra Health, the Fatigue Panel, the Stress Burnout, the Cardiac Panel, or it can be ordered on its own. Walk in during opening hours or call +971 (0)4 379 3562.
Sources
Written from current guidance and reviewed 31 August 2026.
Sources cited above
- Salinas M, López-Garrigós M, Flores E, Leiva-Salinas C. Improving diagnosis and treatment of hypomagnesemia. Clinical Chemistry and Laboratory Medicine. 2024;62(2):234-248. PMID 37503587. doi:10.1515/cclm-2023-0537A review of magnesium testing — including that most magnesium is inside cells and bone, so a normal blood level does not exclude depleted stores.
Sources are listed for the specific statements they support. They are published research and guidance, not a substitute for a consultation — what applies to you is decided by a doctor who has assessed you.
- Magnesium blood testMedlinePlus, US National Library of Medicine
- MagnesiumTesting.com, Association for Diagnostics & Laboratory Medicine
- Blood testsNHS