Magnesium deficiency diagnosed by an intravenous loading test

Area of Science:

• Clinical biochemistry
• Internal medicine
• Nephrology

Background:

• Magnesium deficiency is prevalent yet challenging to diagnose clinically.
• Assessing magnesium status is crucial for managing various medical conditions.

Purpose of the Study:

• To evaluate the efficacy of a magnesium loading test for diagnosing magnesium deficiency.
• To assess magnesium retention in hospitalized patients with conditions affecting magnesium balance.

Main Methods:

• Administered 30 mmol of magnesium sulfate intravenously over 8 hours to 661 hospitalized patients.
• Measured 24-hour urinary magnesium excretion to calculate magnesium retention.
• Compared retention rates between patient groups and control groups (healthy volunteers and non-deficient patients).

Main Results:

• Significantly higher magnesium retention was observed in all patient groups compared to controls (retention ranged from 16% to 38% in patients vs. 3-4% in controls).
• Conditions like congestive heart failure, cerebrovascular events, and alcoholism showed particularly high magnesium retention.
• Serum magnesium levels were similar across most patient groups, except for alcoholics and hypertensives, who had lower levels.

Conclusions:

• The magnesium loading test is a valuable tool for identifying magnesium deficiency in hospitalized patients.
• Many medical conditions are associated with impaired magnesium balance, as indicated by increased retention.
• Magnesium retention correlates with age and renal function, highlighting factors influencing magnesium status.