Diabetes Research Centre, Brussels Free University, B-1090 Brussels, Belgium.
Diabetes Res Clin Pract. 2012 Dec;98(3):459-64. doi: 10.1016/j.diabres.2012.09.042. Epub 2012 Oct 22.
To validate an ELISA method for C-peptide analysis in Cameroon.
We evaluated the linearity, detection limit, functional sensitivity, precision and accuracy, and further investigated for cross-reactivity by proinsulin, and interferences by lipids, bilirubin and hemoglobin. This method was compared with the Roche electrochemiluminescence immunoassay. C-peptide stability was assessed following a series of freeze-thaw cycles, and after storage at room temperature. The C-peptide reference range was determined by analyzing fifty plasma samples of Cameroonians without diabetes.
The ELISA was linear at least up to 7.09 μg/L, and had a detection limit of 0.09 μg/L, and a functional sensitivity of 0.32 μg/L. The inter- and intraassay %CV were 2.9-9.9%, and 5.2-9.4%, respectively. Recoveries were 81-94% in serum, and 93-98% in buffer. Comparison with the ECLIA yielded a good correlation coefficient (R(2)=0.98). There was no cross-reactivity with proinsulin, and no interference with lipids, bilirubin and hemoglobin. C-peptide was stable at room temperature for 24 h and up to 7 freeze-thaw cycles for medium (1-6 μg/L) and high (>6 μg/L) levels (<-15°C and <-70°C). The reference range for C-peptide was 0.38-3.63 μg/L.
This method is suitable for C-peptide analysis in low-income countries like Cameroon.
验证一种用于喀麦隆 C 肽分析的 ELISA 方法。
我们评估了该方法的线性、检测限、功能灵敏度、精密度和准确度，并进一步研究了胰岛素原的交叉反应性，以及脂质、胆红素和血红蛋白的干扰情况。该方法与罗氏电化学发光免疫分析法进行了比较。通过一系列冻融循环和室温储存后，评估了 C 肽的稳定性。通过分析 50 份无糖尿病的喀麦隆人血浆样本，确定了 C 肽的参考范围。
ELISA 方法在至少 7.09 μg/L 范围内呈线性，检测限为 0.09 μg/L，功能灵敏度为 0.32 μg/L。批内和批间 %CV 分别为 2.9-9.9%和 5.2-9.4%。在血清中的回收率为 81-94%，在缓冲液中的回收率为 93-98%。与 ECLIA 的比较产生了良好的相关系数（R²=0.98）。与胰岛素原无交叉反应性，与脂质、胆红素和血红蛋白无干扰。C 肽在室温下 24 小时稳定，在中（1-6 μg/L）和高（>6 μg/L）水平下（<-15°C 和 <-70°C）可进行多达 7 次冻融循环（-15°C 和 <-70°C）。C 肽的参考范围为 0.38-3.63 μg/L。
该方法适用于喀麦隆等低收入国家的 C 肽分析。
