ABSTRACT
Magnesium and calcium metabolism are closely related mainly through the action of the parathyroid hormone. Hypomagnesemia may occur with inadequate dietary intake of magnesium, malabsortion, alcohol addition, diarrhea, renal loss, and other conditions. Automated colorimetric or fluorometric methods for magnesium measurements have proven useful in the clinical laboratories, although atomic absorption spectroscopy procedures are probably more reliable. Unfiltered serum ionized magnesium values obtained by the ion-selective magnesium electrode correlated highly with the ultrafiltered serum magnesium values obtained by atomic absorption spectroscopy. The magnesium loading test has been used by a number of investigators to assess the magnesium status in various patient groups. Urinary magnesium excretion levels above the dietary intake may suggest renal tubular dysfunction while a low urinary output may indicate a malabsorption problem. Ionized magnesium levels in serum appear to be a more useful indicator of magnesium deficiency status and for diagnostic purposes in the clinical environment.
