Magnesium Blood Test

Magnesium Blood Test

This test measures the level of magnesium in your blood. Magnesium is an essential mineral that your body needs for many everyday functions, including healthy muscles and nerves, steady energy production, a regular heartbeat, and strong bones. It also works closely with other minerals such as calcium and potassium.

Magnesium levels that are too low or too high can both affect how you feel and how your body works. Low magnesium is the more common concern and can be linked to things such as muscle cramps, tiredness, and disturbances in other minerals. This test gives a straightforward picture of your current blood magnesium level.

What this test measures

• Magnesium (serum)

When it may be useful

• To check your magnesium level if you have symptoms such as muscle cramps, weakness, or tiredness
• To look into low levels of other minerals, such as calcium or potassium, which can be linked to magnesium
• To keep an eye on magnesium when it may be affected by diet, digestive problems, or certain medicines
• As part of a wider check of your general health and mineral balance

Good to know

• The blood test measures the magnesium circulating in your blood, which is only a small part of the body's total magnesium, so a normal result does not always completely rule out low overall stores
• Magnesium results are best understood alongside related minerals such as calcium and potassium
• Your GP or clinician will explain what your result means for you and whether any action is needed

Magnesium, Serum

No special preparation required.

For blood tests, we recommend drinking plenty of water beforehand to ensure smooth sample collection. If you are taking any regular medication, continue to do so unless advised otherwise by your doctor.