Bodo von Ehrlich

Background/Objectives: Reliable markers of human magnesium (Mg) status are needed. Methods: Current Mg studies report ratios between serum Mg and calcium (Ca) using four interchangeable expressions (i.e., molar or weight calculations of Mg/Ca or Ca/Mg). We propose a scale using ratios of serum Mg and Ca to assess Mg status, unified for all four expressions. We explore its application for case studies and published research. Results: Case Studies (4)—the proposed serum Mg/Ca scale showed better Mg diagnostic value than serum Mg alone. Published Studies—A. The proposed Mg/Ca scale’s “depleted Mg” status predicted mortality among hospitalized COVID-19 patients in ROC/AUC analyses. B. The serum Ca/Mg proposed scale, when applied to “healthy” adults with “normal” serum Mg, exposed a “seriously depleted” to “adequate” range of Mg status. C. In a study of periodontal disease, patients designated “adequate” or “mild” Mg depletion by the proposed scale showed greater 5-year improvement than those with scale’s “moderate to serious” Mg depletion status. D. Finally, the proposed scale demonstrated appropriate diagnostic value of serum Ca/Mg in acute coronary syndrome patients only when “corrected Ca” was NOT used in ratio calculation. Conclusions: The proposed scale needs both total serum Ca and Mg measures in identical units, i.e., mg/dL or mg% (for weight ratios); mmol/L or mEq/L (for molar ratios). Authors/reviewers/editors need to take care when reporting units/methodology of serum Mg and Ca ratios for clear reporting as to weight or molar ratio and use of total or corrected values. Future trials and statistical testing are needed to determine whether ratios between serum Mg and Ca yield more precise measures of physiological Mg status than serum Mg alone. Our findings indicate the proposed scale is worthy of further study as a marker of Mg deficit.

Background/Objectives: Calcium (Ca) and magnesium (Mg) are mutual antagonists that interact in a majority of physiological processes. Thus, maintaining a balance between these two minerals is essential for functional homeostasis. Mg deficiency plays a role in the course and severity of a wide range of chronic health conditions. This knowledge, however, has not translated into active incorporation of serum Mg determination as a reliable diagnostic tool for physiological Mg deficit. Methods: Pioneering work by von Ehrlich and Rosanoff has prompted development of a simple algorithm and scale for using serum Ca and Mg determinations to identify subclinical (i.e., “hidden”) physiological Mg deficiencies. This novel serum Mg/Ca–Ca/Mg scale uses determinations of total serum Ca and Mg and their ratios to alert clinicians to avoidable risks associated with chronic latent Mg deficiency. This review applies this scale to 10 published clinical studies reporting the serum (or plasma) ratio between Mg and Ca. Results: In all 10 studies, application of the serum Mg/Ca–Ca/Mg scale diagnosed deficit Mg status more reliably than serum Mg alone. Conclusions: This review provides both illustrations of the value of the novel scale and support for its consideration in clinical practice and Mg research.

Purpose Serum magnesium is the most frequently used laboratory test for evaluating clinical magnesium status. Hypomagnesemia (low magnesium status), which is associated with many chronic diseases, is diagnosed using the serum magnesium reference range. Currently, no international consensus for a magnesemia normal range exists. Two independent groups designated 0.85 mmol/L (2.07 mg/dL; 1.7 mEq/L) as the low cut-off point defining hypomagnesemia. MaGNet discussions revealed differences in serum magnesium reference ranges used by members’ hospitals and laboratories, presenting an urgent need for standardization. Methods We gathered and compared serum magnesium reference range values from our institutions, hospitals, and colleagues worldwide. Results Serum magnesium levels designating “hypomagnesemia” differ widely. Of 43 collected values, only 2 met 0.85 mmol/L as the low cut-off point to define hypomagnesemia. The remainder had lower cut-off values, which may underestimate hypomagnesemia diagnosis in hospital, clinical, and research assessments. Current serum magnesium reference ranges stem from “normal” populations, which unknowingly include persons with chronic latent magnesium deficit (CLMD). Serum magnesium levels of patients with CLMD fall within widely used “normal” ranges, but their magnesium status is too low for long-term health. The lower serum magnesium reference (0.85 mmol/L) proposed specifically prevents the inclusion of patients with CLMD. Conclusions Widely varying serum magnesium reference ranges render our use of this important medical tool imprecise, minimizing impacts of low magnesium status or hypomagnesemia as a marker of disease risk. To appropriately diagnose, increase awareness of, and manage magnesium status, it is critical to standardize lower reference values for serum magnesium at 0.85 mmol/L (2.07 mg/dL; 1.7 mEq/L).