The Stability of Analytes of Ionized Magnesium Concentration and Its Reference Range in Healthy Volunteers

Abstract

This study aimed to determine the stability of refrigerated analytes of iMg concentration at different time intervals and to establish iMg reference range in a cohort of healthy Omani volunteers (≥18 years). The concentrations of iMg were measured using the direct ion-selective electrode technique. Pearson’s and Lin’s concordance correlation coefficients along with the Bland–Altman plot were used to assess the levels of agreement between iMg concentrations of fresh and refrigerated blood samples at different time intervals. The study included 167 volunteers (51% females) with a median age of 21 (range: 20–25) years. The median, 2.5th, and 97.5th percentiles for fresh iMg reference ranges were 0.55, 0.47, and 0.68 mmol/L, respectively. The overall agreement between the fresh and refrigerated iMg concentrations was poor (rho-c = 0.51; p < 0.001). However, according to Altman’s definition, iMg concentrations of the refrigerated samples for a period of ≤1 h had an excellent correlation with the fresh iMg concentrations (Lin’s rho-c = 0.80), with a small average bias difference of 0.009 (95%CI; −0.025–0.043). A cut-off refrigeration period within ≤1 h at 2–8 °C can be considered an alternate time frame for the gold standard measurement (fresh or within 0.5 h).

Prevalence of Dysmagnesemia among Patients with Diabetes Mellitus and the Associated Health Outcomes: A Cross-Sectional Study

“…These conditions may restrict the generalizability of the findings. Moreover, the study assessed total magnesium concentrations instead of focusing on ionized magnesium, the biologically active form [36].…”

Dysmagnesemia Measured by Ionized and Total Body Concentrations Among Medically Hospitalized Patients: Incidence, Clinical Characteristics, and Health Outcomes - A Prospective Cohort Study

“…All samples were analyzed in the medical ward by trained research assistants, either immediately or within 1 hour after collection, to ensure the stability of the samples and further details can be found elsewhere. (12)…”

“…For iMg concentration measurement: hypomagnesemia was de ned based on a local Omani population reference range as an initial iMg concentration of ≤ 0.46 mmol/L, while hypermagnesemia was determined by an iMg concentration of ≥ 0.69 mmol/L. (12) For tMg concentration measurement: hypomagnesemia was de ned as a tMg concentration of ≤ 0.69 mmol/L, and hypermagnesemia was de ned as a tMg concentration of ≥ 1.01 mmol/L. (6)…”

“…(13) However, recent observational studies and clinical trials have not found a statistically signi cant positive correlation between tMg and iMg using Pearson's correlation coe cients (with correlation values ranging from 0.50 to 0.77). (12,14) This study aimed to determine the incidence of dysmagnesemia using iMg and tMg concentrations among patients hospitalized in medical wards, as well as their correlation. The associated clinical and biochemical characteristics as well as health outcomes were also assessed.…”