Abstract

The assay in serum of non-caeruloplasmin copper, as exchangeable copper after complexation with EDTA (ExCu) and total copper has been evaluated and compared in patients with varying c-reactive protein(CRP).

Measurement of ExCu and total copper, range 0.2–47.2 µmol/L, was developed using ICP-MS. The chelating agents EDTA and TEPA were compared over 0.0–10 g/L after incubation with serum for 60 mins followed by ultrafiltration with Amicon 10 kDa filter. The assay for ExCu was optimised with EDTA 3 g/L (8.1 mmol/L) maintained at pH 7.0–8.0 before ultrafiltration. TEPA was not as selective in chelation of copper. Patients n = 82 were studied in relation to changes in inflammatory marker CRP and a group of patients n = 37 with normal CRP.

The ExCu assay gave excellent recoveries (94–102 % but poor recovery for free uncomplexed copper), good repeatability, limit of quantitation 0.19 µmol/l with a provisional reference range 0.48 to 1.63 µmol/L (n = 37 patients). The range for relative exchangeable copper (exchangeable copper divided by total serum copper) was 2.49 to 9.96 %. ExCu was elevated in conditions with increased CRP greater than 100 mg/L suggesting an effect of inflammation on the free copper fraction.

A reliable and reproducible assay for ExCu and total copper has been developed. The upregulated inflammatory state increases the ExCu suggesting excess free copper.

摘要

血清中非铜蓝蛋白铜的检测，作为与 EDTA (ExCu) 和总铜络合后的可交换铜，已在具有不同 c 反应蛋白 (CRP) 的患者中进行了评估和比较。

ExCu 和总铜的测量范围为 0.2–47.2 µmol/L，是使用 ICP-MS 开发的。螯合剂 EDTA 和 TEPA 在与血清一起孵育 60 分钟后比较 0.0–10 g/L，然后用 Amicon 10 kDa 过滤器进行超滤。在超滤前，使用 EDTA 3 g/L (8.1 mmol/L) 保持 pH 7.0–8.0 对 ExCu 的测定进行了优化。TEPA 在螯合铜方面没有那么高的选择性。 研究了n = 82 名患者的炎症标志物 CRP 变化和一组患者n  = 37 名 CRP 正常的患者。

ExCu 测定获得了极好的回收率（94–102% 但游离未络合铜的回收率较差）、良好的重复性、定量限为 0.19 µmol/l，临时参考范围为 0.48 至 1.63 µmol/L（n  = 37 名患者）。相对可交换铜（可交换铜除以总血清铜）的范围为 2.49% 至 9.96%。ExCu 在 CRP 增加大于 100 mg/L 的条件下升高，表明炎症对游离铜部分的影响。

已开发出一种可靠且可重复的 ExCu 和总铜测定法。上调的炎症状态增加了 ExCu，表明游离铜过多。