Normal Reference Ranges
Adult
6.0 - 10.0 mEq/day
Pediatric
Varies by age mEq/day
Clinical Significance
Helps differentiate renal vs. extra-renal causes of hypomagnesemia. Elevated 24-hr excretion indicates renal wasting.
Causes of High
- Renal magnesium wasting (Gitelman / Bartter syndrome)
- Diuretics
- Hypercalcemia
Causes of Low
- Gastrointestinal magnesium malabsorption
- Low dietary intake