I don’t necessarily think a person needs to have their magnesium levels tested before taking magnesium. It’s a very safe mineral that does not build up in the body. If you take “too much” magnesium, you will just get the laxative effect that eliminates the excess. However, if you are on a handful of drugs and ask your doctor if you can take magnesium, they may just say no. Or they will do a standard serum magnesium test, which usually turns up normal.
Serum magnesium is a very inaccurate measurement of magnesium in the body. Magnesium in the blood stream, AKA serum magnesium, measures only 1% of the total body magnesium; the range is 1.8-3.6mg/dL. When serum magnesium drops, mechanisms in the body push the levels up by dragging magnesium out of the bones and muscles. This is done for a very important reason – the heart muscle requires a constant level of magnesium or it will go into spasm – AKA a heart attack!
A somewhat better test is the Magnesium RBC. It may measure 40% of the body’s total magnesium. The range is 4.2-6.8mg/dL. But don’t be fooled into thinking that if your level is 4.2 you have enough magnesium. Someone recently wrote asking my source for the optimum range of magnesium being 6.0-6.5mg/dL. He asked if this tighter range comes from research, or did I arrive at it empirically. He also said that his nutritional-metabolic doctors were unaware of using 6 as the floor instead of 4.
Empirically means: Verifiable or provable by means of observation or experiment. Yes, I arrived at this level empirically. Since 80% of the population is deficient in magnesium and since the lab ranges are taken from the general population – I don’t want to be lumped into the deficient 80%, I want my magnesium levels to be in the top 20th percentile, which is 6.0 and above.
In the past year, the Magnesium RBC range has dropped even lower – as the magnesium-deficient population grows!! In some labs the range is now 3.8-6.4. It’s quite devastating for someone who has atrial fibrillation, migraines, insomnia, muscle twitching – all the symptoms of magnesium deficiency to be told that 3.8mg/dl of Magnesium RBC is NORMAL and they are just fine – don’t bother with magnesium, just take these 6 drugs for your symptoms.
Unfortunately for millions of magnesium-deficient victims, Magnesium Therapy is VERY NEW and totally unrecognized. And when magnesium is finally recommended, you are given the wrong forms. Most people cannot get enough magnesium to overcome their deficiency and the magnesium drain from drugs, stress and poor diet.
Don’t forget what I said in the first sentence, you don’t necessarily need a magnesium blood test. And, even if your test looks good but you still have magnesium deficiency symptoms, go by how you feel, not the test.
Carolyn Dean, MD, ND
Here is an article by Health Blogger, Travis Van Slooten, about magnesium testing for additional info:
There are three tests that you can get if you suspect that you are dealing with a magnesium deficiency:
- Serum Magnesium
- RBC Magnesium Analysis
1. Serum Magnesium Testing
Serum magnesium tests require a basic blood draw. They’re the most common way to test for deficiencies. If you see your doctor and ask for a magnesium test, this is the test he’ll prescribe. They’re not always accurate, however. In fact, they are rarely ever accurate.
That’s because serum magnesium tests only test the amount of magnesium in your blood. They don’t measure the amount of magnesium that is present and working within your cells, where the bulk of the magnesium is stored in your body.
Despite its flaws, it’s possible to draw some correlations. If your serum blood magnesium levels are low then chances are your actual magnesium levels are low (and probably very low). If your blood magnesium levels are higher than normal then you probably have enough magnesium in your cells.
The problem arises when the test shows your blood magnesium levels to be normal, which is usually what happens. With a normal reading, most doctors will simply say that you have adequate levels of magnesium and move on. The problem is, for most afibbers a normal test result usually means they are actually low in magnesium.
Read this post where I compared my serum magnesium tests to other more advanced testing options (see below).
2. RBC Magnesium Test
An RBC Magnesium test is a more accurate test than serum testing. It also requires a blood draw, but the blood undergoes different tests than it would undergo in a standard serum magnesium test.
You can request a RBC test from your doctor but he’ll likely ignore your request and just prescribe a serum test or tell you that a serum test is “good enough” to determine if you have a magnesium deficiency. Don’t buy it. Demand a RBC test and if they can’t do it, use an independent lab to have one done.
The normal reference range for the RBC magnesium test is 4.2 – 6.8 mg/dL. Dr. Carolyn Dean, the author of the Magnesium Miracle, wrote a blog post about the RBC Magnesium blood test. In it, she wrote you want to be at least 6.0-6.5 mg/dL.
I reached out to her to ask her why she recommended that and she said 80% of the population is deficient in magnesium. As a result, she tells people they want to be above the 80th percentile of their test levels.
In this post I compare my RBC test results with the EXA Test.
3. EXA Test
Finally, there’s the EXA test. This is the current gold standard for testing for magnesium levels. For this test, the inside of your cheeks are scraped with a piece of plastic and then wiped on a test strip and sent in for analysis. Those cheek cells are then scanned by an electron microscope and bombarded with X-rays.
As EXAtest.com explains, this bombardment causes different minerals in your cells to release energy. “From this process, the computer calculates a spectral fingerprint for each patient that identifies the mineral electrolyte levels and ratios within the cell.” EXA tests are the most accurate magnesium tests available today.
Unfortunately, they are not common and are expensive ($295). If you ask your doctor for an EXA test he will very likely give you a blank stare. Most doctors haven’t even heard of this test. I had to contact several naturopathic doctors in my city to find one that administered it. Of course he had an additional charge to administer the test so the total costs for an EXA test can easily exceed $400, which is usually not covered by insurance.
So which test should you have done?
Understand that doctors are typically only going to give the basic blood serum test. They typically won’t offer the other two tests because they usually aren’t readily available and are expensive – and in the case of the EXA test probably haven’t even heard of it!
Skip the blood serum test. It’s meaningless to afibbers. Most people, however, should have easy access to a RBC magnesium test. I would start there. It’s not the most accurate test but it will give you a decent indication if your magnesium levels are too low.
If you have the money and can find someone to administer the EXA test in your area, then it’s a no-brainer. You go with the EXA test as it will give you the most accurate indication of your magnesium levels.
Note: The Nutritional Magnesium Association (NMA) does not receive any remuneration or commission on any of these tests. These links are only for informational purposes and are not an endorsement by the NMA. Please do your own research and investigation into these testing services.
The ideas, procedures and suggestions contained in this article are not intended as a substitute for consulting with your physician. All matters regarding your physical health require medical supervision. Neither the author nor the publisher shall be liable or responsible for any loss, injury or damage allegedly arising from any information or suggestion in this article.