From the Guidelines
Intracellular magnesium measurement is crucial for accurately assessing true magnesium status in the body, as standard serum magnesium tests only measure the 1% of magnesium found in blood, while 99% of magnesium is stored inside cells, particularly in muscles and bones. This is supported by the British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults 1, which highlights that magnesium deficiency has been reported to occur in 13–88% of patients with IBD, but serum magnesium is not an accurate measurement of magnesium status.
The importance of intracellular magnesium measurement is further emphasized by the ESPEN guidelines on parenteral nutrition: gastroenterology 1, which notes that magnesium deficiency may occur despite a normal serum concentration, and it is ideal to measure 24-hour urine magnesium loss. The American Gastroenterological Association medical position statement: short bowel syndrome and intestinal transplantation 1 also supports this, stating that magnesium deficiency may occur despite a normal serum concentration, and it is prudent to measure 24-hour urine magnesium loss.
In terms of clinical implications, the Update to Practice Standards for Electrocardiographic Monitoring in Hospital Settings: A Scientific Statement from the American Heart Association 1 highlights the importance of magnesium in treating torsades de pointes, and notes that hypomagnesemia is associated with more frequent ventricular arrhythmias. The Pharmacologic Prophylaxis: American College of Chest Physicians guidelines for the prevention and management of postoperative atrial fibrillation after cardiac surgery 1 also notes that intracellular magnesium depletion during cardiac surgery may predispose patients to postoperative arrhythmias.
Key points to consider include:
- Intracellular magnesium measurement provides a more complete picture of magnesium status
- Standard serum magnesium tests are inadequate for assessing magnesium status
- Magnesium deficiency can occur despite normal serum levels
- Intracellular testing methods like red blood cell magnesium, ionized magnesium, or magnesium loading tests can help identify magnesium deficiency
- Patients with conditions like diabetes, cardiovascular disease, or those taking medications that deplete magnesium may benefit from intracellular magnesium measurement.
Overall, intracellular magnesium measurement is essential for accurately assessing magnesium status and preventing related complications, and clinicians should consider intracellular testing in patients with suspected magnesium deficiency, especially those with conditions that increase the risk of magnesium depletion 1.
From the Research
Importance of Intracellular Magnesium Measurement
- Intracellular magnesium measurement is important because magnesium is an essential ion in the human body, playing a crucial role in various metabolic and biochemical processes 2, 3.
- It is involved in over 300 enzymatic reactions, including energy metabolism and protein synthesis, and is the second most abundant intracellular cation after potassium 2.
- Hypomagnesemia, or low magnesium levels, is a frequent finding in hospitalized patients, and normal serum magnesium levels may not accurately reflect intracellular magnesium depletion 2, 4.
- Intracellular magnesium measurement can help identify patients at risk of magnesium deficiency, which can have significant clinical consequences, including cardiovascular disease 5, 6.
Clinical Significance of Intracellular Magnesium Measurement
- Intracellular magnesium levels have been shown to be negatively associated with common carotid intima-media thickness, a marker of atherosclerosis, in haemodialysis patients 6.
- Magnesium deficiency has been implicated in various diseases, including cardiovascular disease, and intracellular magnesium measurement can help identify patients at risk of these conditions 3, 5.
- The measurement of intracellular magnesium can provide valuable information for the diagnosis and treatment of magnesium-related disorders, and can help guide replacement therapy 2, 4.
Methods of Intracellular Magnesium Measurement
- Various methods have been proposed for measuring intracellular magnesium, including the determination of magnesium levels in isolated peripheral lymphocytes 6.
- These methods can provide a more accurate assessment of magnesium status than serum magnesium levels alone, which may not reflect intracellular magnesium depletion 2, 3.