We appreciate the comments of Kuiper and apologize for misstating the normal range of values for serum magnesium given in our clinical report.1 In our submission, the serum magnesium values of the patient under discussion were given correctly, at 0.69 mmol/L on admission, and 9.85 mmol/L at the peak. We submitted the normal range for serum magnesium from our laboratory as 0.75 to 1.5 mmol/L. In one instance, the normal range was submitted incorrectly as 3.9 to 6.1 mmol/L. Unfortunately, this error was recognized only after the article went to press. We submitted no laboratory values or normal ranges in units of milligrams per deciliter. These were apparently calculated and added on by the editors of the Archives and, as pointed out by Kuiper, were incorrect.
These errors exemplify that much confusion exists regarding both conversion of serum values of magnesium, and, as illustrated by the case report, conversion