Lenters-Westra Erna, Slingerland Robbert J
Department of Clinical Chemistry, Isala klinieken, Zwolle, The Netherlands.
J Diabetes Sci Technol. 2009 May 1;3(3):418-23. doi: 10.1177/193229680900300303.
Point-of-care instruments for the measurement of hemoglobin A1c (HbA1c) may improve the glycemic control of people with diabetes by providing a rapid result if the performance of the instruments used is acceptable. A 0.5% HbA1c difference between successive results is considered a clinically relevant change. With this in mind, the In2it from Bio-Rad and the DCA Vantage from Siemens were evaluated according to Clinical and Laboratory Standards Institute (CLSI) protocols.
The CLSI protocols EP-5 and EP-9 were applied to investigate precision, accuracy, and bias. The bias was compared with three certified secondary reference measurement procedures. Differences between capillary and venous blood were investigated by an end-user group consisting of nurse practitioners at a diabetes care center.
At HbA1c levels of 5.1 and 11.2%, total coefficients of variation (CV) for the In2it were 4.9 and 3.3%, respectively, and for the DCA Vantage were 1.7 to 1.8% and 3.7 to 5.5% depending on the lot number of the cartridges. Method comparisons showed significant lot number-dependent results for the In2it and the DCA Vantage compared with the three reference methods. No overall difference was observed between capillary and venous blood for both methods.
Performance results of the In2it and the DCA Vantage showed variable and lot number-dependent results. To maintain the interlaboratory CV of 5% for HbA1c, the Clinical Laboratory Improvement Amendments rules for waived point-of-care instruments should be revised. An obligation for participating in external quality schemes and taking adequate action should be considered for POC instruments that perform poorly.
用于测量糖化血红蛋白（HbA1c）的即时检测仪器，如果其性能可接受，通过提供快速检测结果，可能会改善糖尿病患者的血糖控制。连续检测结果之间0.5%的HbA1c差异被认为具有临床相关性变化。考虑到这一点，根据临床和实验室标准协会（CLSI）的方案对伯乐公司的In2it和西门子公司的DCA Vantage进行了评估。
应用CLSI方案EP-5和EP-9来研究精密度、准确性和偏差。将偏差与三种经过认证的二级参考测量程序进行比较。由一家糖尿病护理中心的执业护士组成的最终用户组对毛细血管血和静脉血之间的差异进行了研究。
在HbA1c水平为5.1%和11.2%时，In2it的总变异系数（CV）分别为4.9%和3.3%，DCA Vantage的总变异系数根据试剂盒批号不同在1.7%至1.8%和3.7%至5.5%之间。方法比较显示，与三种参考方法相比，In2it和DCA Vantage的结果存在显著的试剂盒批号依赖性。两种方法在毛细血管血和静脉血之间均未观察到总体差异。
In2it和DCA Vantage的性能结果显示出变异性和试剂盒批号依赖性。为使HbA1c的实验室间CV保持在5%，应修订即时检测仪器的《临床实验室改进修正案》规则。对于性能较差的即时检测仪器，应考虑其参与外部质量计划并采取适当行动的义务。
