Evaluation of an ionized magnesium-pH analyzer--NOVA 8
| Autor: | R Jordal, M Seibaek, B Juul-Jørgensen, H Elming, E Borresen, J Thode |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Adult
Male Clinical Biochemistry Analytical chemistry chemistry.chemical_element Calcium pCO2 chemistry.chemical_compound Reference Values Cations Humans Magnesium Magnesium ion Aged Aged 80 and over Analysis of Variance Aqueous solution Chemistry Albumin Reproducibility of Results General Medicine Nova (laser) Carbon Dioxide Hydrogen-Ion Concentration Middle Aged Reference Standards Phosphate Linear Models Female Ion-Selective Electrodes |
| Zdroj: | Scandinavian journal of clinical and laboratory investigation. 58(2) |
| ISSN: | 0036-5513 |
| Popis: | An ion-selective analyzer (NOVA 8 [previously NOVA CRT], NOVA Biomedical Waltham, USA) for simultaneous measurement of the concentration of ionized magnesium (cMG2+) and pH is investigated for linearity and influence of calcium ions on the Mg2+ results in different Mg2+ aqueous solutions with/without added calcium. Within the cMg2+ range 0-3.0 mmol/L, which covers most clinical values, we found cMg2+ values close to the line of identity, with a sensitivity about 94%, but 0.09 mmol/L lower in the absence of Ca2+. The analytical precision (CV) for human serum control was 1.7% in the physiological range. The accuracy and precision data for the Mg2+ electrode meet the demands for reliable results within the range for clinical use. We found a reference interval (95%) for cMg2+ of between 0.43 and 0.59 mmol/L serum, with a mean value of 0.51 mmol/L for healthy adults in the non-fasting state with no relation to sex or age. The mean cMg2+ was 61% of the mean concentration of plasma total magnesium (cTMg) ranging from (95%) 49% to 73%. No significant correlation was found between cMg2+ and total protein, albumin, phosphate, Ca2+, and total CO2. No significant difference was found between mean values for cMg2+ in whole blood, plasma, and serum. Serum samples could be stored for 24 h at 4 degrees C without significant change. Storage at -20 degrees C for 7 months caused a mean cMg2+ decrease of 8.3%. The mean slope delta lgcMg2+/delta pH measured after equilibration with different pCO2 values in each serum sample from the reference population was -0.0110, indicating a close agreement between the values for actual cMg2+ and adjusted cMg2+ (pH = 7.4). |
| Databáze: | OpenAIRE |
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