Methods established for the detection of mineral levels in whole blood by the dried blood spot technique

Mineral are intimately related to human health and disease, and detection of mineral content in the body is of great significance for the diagnosis and prevention of diseases. In this study, we validated the method developed to detect magnesium (Mg), copper (Cu), iron (Fe), zinc (Zn), and selenium (Se) levels in dried blood spots (DBS). In accordance with the requirements of the guidelines for the Bioanalytical Method Validation Guidance for Industry, we evaluate the linearity, sensitivity, precision, accuracy and selectivity of the developed methods. In addition, Mg, Cu, Fe, Zn and Se were quantified in 195 older adults using DBS technique, and its accuracy was assessed by comparing the results to those detected by inductively coupled plasma-mass spectrometry (ICP-MS). The method has excellent sensitivity and linear range to cover the concentration range of mineral elements in the general population with the required precision, accuracy and selectivity. The correlation coefficients of Mg, Cu, Fe, Zn and Se levels in blood detected by the DBS technique and ICP-MS were 0.638, 0.823, 0.463, 0.728 and 0.751, respectively (all P < 0.05), which indicated that there was a strong correlation between the detection results of the two methods. More than 95 % of the sample results in the Bland-Altman consistency test were within the acceptable limits of agreement (LOA) range, indicating that they had good consistency. DBS technique has good accuracy and reliability in detecting blood mineral levels in the elderly, suggesting potential in the quantification of mineral level in blood.