电感耦合等离子体质谱法与砷铈催化分光光度法检测尿碘浓度的一致性

Consistency of urinary iodine concentration between inductively coupled plasma mass spectrometry and Sandell-Kolthoff method

目的探讨电感耦合等离子体质谱法(ICP-MS)和砷铈催化分光光度法(S-K法)检测尿碘浓度(UIC)的一致性。方法收集1856例成人空腹尿液样本,通过标准化ICP-MS和S-K法同时检测UIC,同时根据S-K法测定的UIC值分为3组,进行分层分析。采用Spearman等级相关对ICP-MS与S-K法测定的UIC进行相关性分析和非参数检验。采用Passing-Bablok相关图和Bland-Altman差异图评估ICP-MS与S-K法测定的UIC的一致性。结果ICP-MS测定的UIC值显著高于S-K法(159.47μg/L和149.85μg/L,P<0.0001)。Bland-Altman图提示,2种方法测定的平均值存在统计学差异(6.08μg/L,95%CI:4.24~7.92μg/L)。分层分析结果显示,UIC<300μg/L组的相关系数高于UIC≥300μg/L组(0.93和0.89,P<0.001)。ICP-MS与S-K法间的平均差异与UIC呈正相关。结论当UIC<300μg/L时,ICP-MS和S-K法具有可比性。当UIC在300~600μg/L时,在考虑研究目的后,应谨慎比较使用ICP-MS和S-K法测定的UIC值。当UIC>600μg/L时,不建议在碘监测研究中对ICP-MS和S-K法测定的UIC进行直接比较。

Objective To investigate the consistency of urinary iodine concentration(UIC)measured by inductively coupled plasma mass spectrometry(ICP-MS)versus the Sandell-Kolthoff(S-K)method.Methods A total of 1856 adult fasting urine samples were collected.UIC was simultaneously measured by standard ICP-MS and the S-K method.Spearman’s correlation and a nonparametric test of the UIC results obtained by ICP-MS and the S-K method were performed.Passing-Bablok regression and a Bland-Altman plot were used to evaluate the consistency of the UIC results obtained by the two methods.Results The UIC values obtained by ICP-MS were significantly higher than those obtained by the S-K method(159.47 vs 149.85μg/L,P<0.0001).The Bland-Altman plot showed a significant mean difference between the two methods(6.08μg/L,95%CI:4.24-7.92μg/L).A stratified analysis showed that the correlation coefficient of the UIC<300μg/L group was higher than that of the UIC≥300μg/L group(0.93 vs 0.89,P<0.001).The mean difference between ICPMS and S-K method was positively correlated with UIC.Conclusion When the UIC is less than 300μg/L,the ICP-MS and S-K method are comparable.When the UIC is 300-600μg/L,the UIC values obtained by the two methods should be carefully compared after considering the research purpose.If the UIC is greater than 600μg/L,we do not recommend direct comparison of the UIC obtained by ICP-MS and S-K method for iodine monitoring studies.