Article Text

  1. J. R. Rylander,
  2. S. R. Stoltz
  1. Department of Medicine, UCSF-Fresno, Fresno, CA


Purpose Abnormal serum magnesium values are commonly encountered in a wide spectrum of patients. However, except in unique circumstances, it is unclear whether or not minor magnesium abnormalities even require treatment or whether correction of the magnesium level to normal has any bearing on patient morbidity and mortality. During the past few years, there seems to have been a substantial increase in routine serum magnesium testing on patients admitted to hospitals. The primary objective of this study is to document the changes in the quantity of routine magnesium testing done on patients within a large community hospital setting. A second objective of the study is to measure the excess costs of unnecessary magnesium testing.

Methods To test the hypothesis that there has been an increase in magnesium testing, two time periods were chosen for comparison: July 1, 1999 to June 30, 2000 and July 1, 2003 to June 30, 2004. Total magnesium lab tests were obtained from laboratory services and hospital administration at three hospitals in Fresno, California-Clovis Community Hospital (CCH), Fresno Community Hospital (FCH), and University Medical Center (UMC). For each time frame, 100 random patient charts were reviewed by the authors to determine whether or not magnesium testing was necessary.

Results The current patient charge for magnesium testing is $98.00 for inpatient and $54.00 for outpatient. Medicare reimbursement is $9.36. For the July 1, 1999 to June 30, 2000 time period there were a total of 28,457 magnesium lab tests performed (904 at CCH; 8,637 at FCH; 18,916 at UMC). This compares with the July 1, 2003 to June 30, 2004 time period when 38,830 magnesium lab tests were performed (2,917 at CCH; 15,265 at FCH; 20,648 at UMC). The percent change in magnesium testing for each hospital is as follows: +222.7% at CCH; +76.7% at FCH; and +9.2% at UMC. Based on the authors' own scoring system, during the 1999-2000 year, 55% of all magnesium testing was unnecessary while for the 2003-2004 year 54% of all testing was unnecessary.

Conclusions Even when corrected for changes in hospital volumes, there has been a substantial increase in the ordering of routine magnesium levels. With more than half of all magnesium tests unnecessary, patients could be spared the added costs of such testing.

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