Status of the mononuclear blood cell magnesium assay.

The tenth anniversary for the determination of magnesium in MBC shows progress, but fundamental questions are still unanswered. Uniformity of the methodology for the assay and the units for reporting the result is a key factor for the validity and comparability of results. There is relatively good agreement among investigators for the mean value of magnesium in MBC expressed with three different units. The MBC magnesium results do not correlate with serum or red blood cell magnesium concentrations in humans. There may be a correlation for magnesium between MBC and muscle and between magnesium and potassium in MBC. The correlation for magnesium between MBC and muscle or other body tissues, particularly bone, needs to be defined for the clinical utility of the assay. A number of studies to date suggest a possible clinical utility for the MBC magnesium assay in several disease entities. Thus, the MBC magnesium assay has come a long way in a relatively short time. The future for the assay is uncertain but does hold hope that this relatively simple test can provide useful information about intracellular or total body magnesium status.