I recently read an article by Madias et al1 entitled "Admission Serum Magnesium Level Does Not Predict the Hospital Outcome of Patients With Acute Myocardial Infarction," which appeared in the August 12/ 26, 1996, issue of the Archives. While the determination of magnesium (Mg) levels may be very useful to a practicing clinician, not only in patients with myocardial infarction but also in patients with other problems such as bronchial asthma and fibromyalgia,2,3 it should be pointed out that just because a serum Mg level is within normal range the patient's total body Mg status may not be normal. In a patient with myocardial infarction, one should be interested not only in the serum Mg levels but also in the myocardial (ie, tissue) Mg level.
I am a rheumatologist and have found that my patients with fibromyalgia as a group have a lower mean red blood cell Mg
Romano TJ. Serum Magnesium Levels May Not Indicate Low Tissue Magnesium Levels. Arch Intern Med. 1997;157(4):460. doi:10.1001/archinte.1997.00440250120014