Update on the assessment of magnesium status.
Level 5 - mechanism / opinion, no new human data
Narrative review of diagnostic approaches without systematic methodology
PubMed 18598586 · doi:10.1017/S000711450800682X
What was done
The author reviewed existing and emerging laboratory methods for assessing total body magnesium status in humans, evaluating serum levels, loading tests, cellular measurements, tissue biopsies, and non-invasive technologies.
What was found
Serum magnesium below 0.75 mmol/l identifies severe deficiency, whereas concentrations between 0.75 and 0.85 mmol/l require a magnesium loading test to detect deficiency. The loading test serves as the gold standard but is unsuitable in patients with disturbed renal or intestinal function when given orally. Cellular measurements (total or ionized) frequently disagree, and muscle or bone measurements require invasive biopsies.
Why it matters
This review outlines diagnostic cutoffs for clinical practice while highlighting the persistent lack of a simple, rapid, and accurate single test to assess whole-body magnesium stores.
Limits
This is a narrative review with no systematic search methodology, quantitative synthesis, or participant count provided in the abstract. Magnesium loading test protocols also lack cross-clinic standardization.
Cited by
- supports Standard blood draw tests for magnesium do not reflect total body magnesium status because the majority is stored in bone and serum levels are transient.