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Variability of ionic magnesium

dc.contributor.advisorNewhouse, Ian
dc.contributor.authorJohnson, Kristien Paul
dc.description.abstractWith the invention o f the ion-selective electrode, ionic magnesium (iMg), the biologically active form of Mg, is a common blood assay. There is some evidence that iMg has considerable within subject variability. To further assess this, blood samples were collected from 13 healthy volunteers 6X/day (7:00 - 22:00, every 3 hours) for 3 consecutive days and analysed for iMg (NOVA Stat 8 Analyser). Individual ranges averaged .08 mmol/L (range .05 to .14). Coefficients of variation (CV) ranged from 3% to 7% (mean 4%) while analytical variation was determined to be 2.3%. Biological variability thus accounts for almost half of the variability which is clinically significant as 9 of the 13 subjects recorded at least one value below a reference range of .46 - .60 mmol/L. A significant within day variation (p<.001) was noted, with differences between 7:00 and 10:00 as well as 10:00 and 22:00. Between day variations were not significant (p=.56). A plausible explanation of this data is that iMg has a circadian rhythm, but a sinusoidal curve of best fit computed for each subject did not correlate highly to iMg (r=.20). Thus, cautious interpretation of iMg values is warranted until future research determines the nature of iMg variability.
dc.subjectElectrodes, Ion selective
dc.subjectMagnesium ions
dc.subjectMagnesium in the body
dc.titleVariability of ionic magnesium
dc.typeThesis of Science University
dc.contributor.committeememberMcAuliffe, Jim
dc.contributor.committeememberMontelpare, William

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