一种新的谷氨酸脱羧酶抗体阳性判断标准的建立

目的:建立一种新的谷氨酸脱羧酶自身抗体(glutamicaciddecarboxylaseautoantibody,GAD鄄Ab)阳性判断标准,并应用于临床。方法:采用改良放射配体法检测GAD鄄Ab,结果用GAD鄄Ab指数表示,以109名正常人GAD鄄Ab指数的99.5%百分位点作为正常上限,检测43例1型和226例2型糖尿病患者血清GAD鄄Ab水平。结果:该方法批内变异系数(CV)为4.9%～8.3%,批间CV为7.1%～10.8%,阳性临界值为0.05,结果判断与国际标准化实验室的一致率为98.3%,Kappa值为0.971,结果判断重复性为100%(102例标本3次检测),优于传统的标准差判断标准。用该标准检测1型糖尿病患者阳性率为58.1%(25/43),2型糖尿病患者为10.2%(23/226),正常人为1.8%(2/109),差异有显著性(P<0.01)。结论:新建立的判断标准灵敏度高、特异度强,一致性和重复性好,可在临床推广应用。

Establishment of a New Method to Evaluate Autoantibodies of Glutamic Acid Decarboxylase

Objective:To establish a new method to assess results of glutamic acid decarboxylase autoantibody(GAD-A b)and to test its clinical application.Methods:Improved radioligand assay was us ed to measure GAD-Ab,the result was shown as GAD-Ab index.One hundred and nine healthy controls were screened for GAD-Ab,and the normal upper range limit was defined as99.5%.Serum levels of GAD-Ab were also measured in43patients with ty pe1diabetes and226patients with type2diadetes.Results:The intra-assay coefficie nts of variation(CV)were4.9%-8.3%,inter-assay CV were7.1%-10.8%.The positive cut-off point for GAD-Ab is0.05.Compared with the international standard,the r atio of consistency reached98.3%,with Kappa value of0.971,and repetition of100%. The positivity of GAD-Ab in subjects with type1di-abetes was58.1%(25/43),type2 diabetes10.2%(23/226),and healthy controls1.8%(2/109)respectively,in which there were significant differences(P<0.01).Conclusions:The new model for GAD-Ab ass essment has a high sensitivity,strong specificity,good consistency and repetitio n.It may be used in clinical practice.