血清胰岛素抗体对胰岛素测定的干扰及纠正方法

目的　测定正常人及糖尿病患者血清游离胰岛素 (freeimmunoreactive insulin ,F IRI)与免疫活性胰岛素 (immunoreactive insulin ,IRI)水平 ,探讨血中胰岛素抗体 (insulinantibodies,IA)对胰岛素测定的干扰及纠正方法。方法　采集正常人和糖尿病人血样 ,聚乙二醇 (PEG)预沉淀除去血清中IA和结合胰岛素 ,用12 5I 胰岛素和胰岛素分别行热、冷回收鉴定 ;采用RIA法分别测定样品IA、IRI和F IRI。结果　IA阳性血样的F IRI热回收率 (5 .87% )显著低于IA阴性者 (98.35 % ) (P <0 .0 1) ,而F IRI冷回收率在IA阴、阳性组间无差异 (P >0 .0 5 ) ;正常人及IA阴性的糖尿病患者 ,血清IRI与F IRI测定值无差异 (P >0 .0 5 ) ;IA阳性的糖尿病患者血清IRI高于F IRI测值 (P <0 .0 5 ) ,而且与餐后相比 ,空腹时IRI与F IRI二者的差异程度更明显 (P <0 .0 5 )。结论　血清内源性IA可干扰IRI放免测定 ,使测定值出现偏差。采用PEG对标本预沉淀后测定F IRI,可排除IA的干扰 ,对了解病情和指导用药有实际意义

Interference of anti-insulin antibody for insulin determination and the corrective procedure

Objective To measure the levels of immunoreactive insulin (IRI) and free-IRI (F-IRI) in sera from normal subjects and diabetes mellitus patients and evaluate the interference of anti-insulin antibodies (IA) for the determination.Methods The hot and cold recovery tests were performed by 125 I-insulin and insulin respectively.IA,IRI,F-IRI in serum samples were evaluated by RIA.IA in serum bound with 125 I-insulin and the concentrations ofIRI and F-IRI were measured by radioimmunoassay (RIA).Results The hot recoveryratios of F-IRI assay in IA-negative and IA-positive serum were different(98.35% vs. 5.87%),but in cold recovery test no difference was found between the two groups(P>0.05).No differences of IRI and F-IRI levels were found between normal subjects and IA-negative DM patients (P>0.05).In IA-positive DM patients,the serum IRI concentration was higher than that of F-IRI (P<0.05),and the ratio of IRI/F-IRI in fasting subgroup was higher than that of postprandial group.Conclusion The concentration of serum IRI determined by RIA may be interfered by endogenous IA.To remove the effects of IA,the serum samples should be pre-precipitated by PEG.The measurement of serum F-IRI concentration is useful for management of insulin-treated diabetics, especially for the IA-positive patients.