Circulating total and ionized magnesium after ethanol ingestion.

Hypomagnesemia is associated with alcoholism (Lim P, Jacob E. Metabolism 1972;21:1045-51). Here we assess two measurements of blood magnesium in emergency care patients with confirmed ethanol ingestion. Serum total and ionized magnesium (tMg, iMg) were measured in 88 patients with ethanol concentrations of 6-128 mmol/L and in sera of 97 hospitalized patients (control group). iMg was measured by an ion-selective electrode method; tMg was measured spectrophotometrically. iMg was significantly lower for the ethanol-containing specimens (0.35 +/- 0.12 mmol/L, mean +/- SD) than for the control group (0.46 +/- 0.15 mmol/L), with P <0.0001. The tMg for the test group (0.87 +/- 0.20 mmol/L) was not significantly different from the controls (0.88 +/- 0.33 mmol/L), with P = 0.5987. tMg was not well-correlated with iMg in the ethanol-positive specimens. Most ethanol-positive patients had abnormally low serum iMg (87 of 88 had iMg <0.53 mmol/L).