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Magnesium Levels and the Difference between Serum and RBC Blood Tests

Magnesium Levels and the Difference between Serum and RBC Blood Tests

17th Oct 2023

Do blood tests show accurate magnesium levels?

Have you ever taken a blood test that showed that your magnesium levels are normal, but still feel as though your sleep and energy levels could benefit from taking a supplement?

A serum magnesium test is the amount of magnesium in the blood serum, which is not as accurate as the RBC (red blood cells) magnesium test, which measures the amount of magnesium in red blood cells. Some people find that even this test doesn’t properly show correct magnesium levels.

A serum test only represents 0.8 per cent of the magnesium your body stores and completely neglects the other 99.2 per cent of magnesium in other tissues. So, you might actually be magnesium deficient but the test shows you’re fine. The RBC magnesium test provides a better understanding of your body’s magnesium levels due to red blood cells’ higher magnesium content, but they’re still not a complete representation. A normal RBC magnesium level ranges between 4.2 and 6.8ml/dL, with some experts recommending a level of 6.0 as the minimum,

A blood test, however, can measure any severe deficiencies, so it’s still important to regularly check how your body is faring.

Taking a magnesium supplement each day is generally safe, even at normal levels, so if you feel as though you could benefit from taking magnesium, do so and observe your symptoms to see if it’s effective. Today, many people are magnesium deficient, so it’s often beneficial to take magnesium supplements as long as you’re also getting enough calcium throughout the day.

Make sure to inform yourself about the different forms of magnesium and their respective benefits to determine which supplement to take.