Serum Trace Element Analysis Protocol

For trace element detection, 5 ml of fasting venous blood sample was collected and placed in a vacuum EDTA-K₂ anticoagulant blood collection vessel. After centrifugation at 3000 rpm for 10 min, the red blood cell fraction and plasma were removed, and the serum was transferred to a deionized cryotube and stored in a refrigerator at -20 °C until element analysis. The serum concentrations of Cu and Zn were evaluated using inductively coupled plasma spectrometry (ICP–MS, PerkinElmer Life and Analytical Sciences, Inc., CT, USA). For male participants with levels less than 0.70 mg/L and more than 1.40 mg/L and for female participants with levels less than 0.80 mg/L and more than 1.50 mg/L, the cut-offs were used to categorize hypo- and hypercupremia, respectively. The normal range of serum Zn levels was 0.76 mg/L to 1.50 mg/L. SCZR was evaluated as an alternative biomarker for assessing clinical outcomes [16 (link)].