In order for you to have normal nerve and muscle function, to be able to metabolize calcium and to have a production of protein, the mineral magnesium is needed. We get magnesium through our diet from, among other things, leafy greens and some animal products. Certain diseases such as gastrointestinal diseases and dietary restrictions can cause magnesium deficiency, which may be one of the reasons for doing a magnesium test.
Why is magnesium important?
Magnesium is a vital mineral that plays a central role in several of the body's functions. It is needed, among other things, for nerves and muscles to function normally, to regulate blood pressure, for the rhythm of the heart, for the production of protein and for the body to be able to metabolize calcium and vitamin D effectively.
Reference range for P- Magnesium
Normal values for adults (≥ 18 years) are:
- Lower reference limit: 0.70 mmol/L
- Upper reference limit: 0.95 mmol/L
Note that reference ranges may vary depending on the laboratory.
What does low magnesium levels mean?
Magnesium deficiency is relatively common, especially in people with malnutrition, gastrointestinal diseases (e.g. Crohn's disease or celiac disease), high alcohol consumption, stress or use of certain medications (such as diuretics or proton pump inhibitors). Symptoms can be diffuse but may include:
- Muscle weakness or muscle cramps
- Numbness or tingling
- Fatigue and general weakness
- Heart palpitations or irregular heartbeat
- Decreased appetite, nausea or vomiting
In severe cases, it can also affect the nervous system and cause psychological symptoms such as anxiety or depression.
What do high magnesium levels mean?
Elevated levels of magnesium in the blood are uncommon but can occur in cases such as kidney failure, when the kidneys are unable to excrete the excess. It can also occur with excessive intake of magnesium supplements. High levels can lead to:
- Fatigue or drowsiness
- Slow heart rate
- Low blood pressure
- Respiratory effects at very high levels
The analysis is based on a venous blood test that measures your magnesium level and indicates whether you have a magnesium deficiency and gives you any indications of lifestyle changes that can adjust your values.
What does a magnesium test measure?
A magnesium test measures the concentration of magnesium in the blood plasma. The test is used to detect and follow up low or high magnesium levels and may be particularly relevant in cases of symptoms, diseases or drug treatments that can affect the body's magnesium balance.
Only a small part of the body's total magnesium is found in the blood. The majority is found in the bones, muscles and other tissues. A normal P-magnesium value therefore does not always rule out that the body's magnesium stores are reduced, but a low value is a clear signal of magnesium deficiency and should be assessed in its medical context.
Magnesium and other electrolytes
Magnesium is closely related to the body's levels of potassium and calcium. In the case of magnesium deficiency, potassium or calcium levels can also be low, and the disorders can sometimes be difficult to correct before the magnesium deficiency is treated.
In the case of a deviating magnesium value, it may therefore be relevant to also analyze potassium, calcium and kidney function. If an effect on mineral metabolism is suspected, phosphate, vitamin D and parathyroid hormone may also be relevant complementary analyses.
Which medications can affect magnesium levels?
Some medications can affect the absorption or excretion of magnesium. Low levels can occur, for example, with long-term use of proton pump inhibitors for acid reflux, certain diuretics and certain cancer treatments. Magnesium supplements, certain laxatives and heartburn medications can instead contribute to elevated levels, especially in people with impaired kidney function. Therefore, always inform about which medications and dietary supplements you are using when the result is assessed.
When may further investigation be needed?
In the case of low magnesium, further investigation may be needed to determine whether the cause is low intake, impaired absorption in the intestine or increased loss through the kidneys. In the case of recurrent or difficult-to-explain magnesium deficiency, magnesium in urine can be analyzed to distinguish between loss via the kidneys and other causes.
A deviating magnesium value should be assessed together with symptoms, kidney function, other electrolytes and any drug treatment. In the event of pronounced muscle weakness, heart rhythm disturbances, seizures or clear general effects, medical care should be contacted.
