几种化学发光检测系统测定血清胰岛素和C-肽临床效果的评估

目的探讨不同化学发光检测系统测定血清胰岛素、C-肽临床结果间的可比性和符合程度,并试图找到不受方法学影响,能够反映两者动态变化规律的通用参数。方法选择40名做胰岛素和C-肽释放试验的患者（均未使用外源性胰岛素治疗）,同时应用三种化学发光免疫分析系统,检测同一个体在OGTT中各时间点血清胰岛素和C-肽的浓度,并分别计算两者在服糖后各时间点浓度与其空腹浓度的比值（简称比值）。结果①血清胰岛素或C-肽测定结果在任意两系统间的差异均非常显著（均为P〈0.001）,且高度相关（胰岛素：r=0.946-0.977;C-肽：r=0.959-0.996）。②服糖后同一时间点胰岛素的上述比值在任意两系统间均显著相关（均为P〈0.05）,且均无统计学差异（均为P〉0.05）,C-肽也可得到相似结果。③对于相同检测系统,同一时间点两者的上述比值间差异显著（P〈0.05）且C-肽的比值显著低于胰岛素。结论血清胰岛素或C-肽的测定结果在不同检测系统间差异很大,虽均具有很好的相关性,但不能互相通用。而在OGTT中,服糖后同一时间点两者浓度与各自空腹浓度的比值在不同检测系统间的差异似乎并不显著,有望成为不同检测系统间互认的指标。至于C-肽在反映胰腺β细胞功能的敏感度上显著低于胰岛素的问题,其临床应用尚有待进一步研究。

Evaluation of clinical effects for different chemiluminescence immunoassay systems of serum insulin and C-peptide

Objective To investigate the comparability and agreement of serum insulin and C-peptide levels detected by different chemiluminescence immunoassay systems,and try to find a common parameter not influenced by detection system to reflect dynamic changes of the two items.Methods Forty patients were selected that had done insulin and C-peptide release test（no exogenous insulin therapy）,insulin and C-peptide concentrations of the same individual at different time points in OGTT were measured simultaneously by three different chemiluminescence immunoassay systems,and the ratio of serum insulin or C-peptide levels after meal at each time point to the corresponding fasting levels was calculated.Results There were significant differences between serum insulin/C-peptide levels detected by any two kinds of detection systems（all P0.001）,and significant correlations were also found（insulin： r=0.946 to 0.977;C-peptide： r=0.959 to 0.996）.Between any two kinds of systems,the ratio of insulin/ C-peptide levels after meal to fasting level at the same time point were significant correlated（all P0.05）,and no significant difference was found（all P0.05）.There was significant difference between the ratio of insulin and C-peptide detected by the same system at the same time point（P≤0.05）.Conclusion Serum insulin or C-peptide levels measured by different chemiluminescence immunoassay systems present with very different absolute values,and could not be interoperable though they highly correlated with each other.However,among different systems,the ratio of insulin or C-peptide levels after meal to fasting levels at the same time point seems to have no statistical difference,which was expected to be a mutual recognition of the different systems.As for the sensitivity of C-peptide was significantly lower than insulin in response to pancreatic β cell function,its clinical application remains to be further explored.