糖化血红蛋白HbA1c研究进展

糖化血红蛋白HbAlc是糖尿病患者的一个重要监测指标，美国糖尿病协会（ADA）已经将其作为糖尿病血糖控制的金标准。HbAlc是糖尿病微血管和大血管并发症的危险因素。近期，ADA又将HbAlc值作为确定糖尿病患者治疗目标的靶值。质量保证计划也将HbAlc作为评估糖尿病护理质量的指标。现对HbAlc的近期研究特别是有关标准化和临床应用等内容作一概述。     

糖化血红蛋白HbA1c研究进展

糖化血红蛋白HbA1c是糖尿病患者的一个重要监测指标,美国糖尿病协会(ADA)已经将其作为糖尿病血糖控制的金标准。HbA1c是糖尿病微血管和大血管并发症的危险因素。近期,ADA又将HbA1c值作为确定糖尿病患者治疗目标的靶值。质量保证计划也将HbA1c作为评估糖尿病护理质量的指标。现对HbA1c的近期研究特别是有关标准化和临床应用等内容作一概述。     

溶血剂溶血效果对HbA1c测定的影响分析

目的 探讨不同溶血时长下的溶血剂溶血效果对糖化血红蛋白测定结果的影响.方法 取5例患者的末梢血,各样本经溶血处理后在24 h内分7个时间点,采用散射比浊法测定各样本的糖化血红蛋白值.结果 检测结果经F检验得出:5份溶血样本在7个时间点所测糖化血红蛋白结果差异无统计学意义(P>0.05).结论 低温冷藏条件下,溶血剂溶血效果在24 h内保持稳定,HbA1c检测结果无显著性变化.     

HbF变异体对三种不同HbA1c检测系统的干扰评价

目的 评价血红蛋白变异体F(HbF)对三种糖化血红蛋白(HbA1c)检测系统测定结果的干扰。三种方法分别为离子交换高效液相色谱法(IE-HPLC)、硼酸盐亲和层析高效液相色谱法(AC-HPLC)和免疫抑制比浊法。方法 分别用三种检测系统检测血红蛋白结构正常标本及含有胎儿血红蛋白(HbF)的标本,依据美国国家糖化血红蛋白标准化计划(NGSP)的判定标准,对检测结果进行比对分析和偏倚评估。结果 以Primus Ultra2(AC-HPLC)为比较系统,IE-HPLC和免疫比浊法为检测系统,两种检测系统与比较系统检测正常样品HbA1c值的相关性良好。当HbF≤8.75%时,IE-HPLC测定结果与比较系统偏差<6%; HbF为17.50%时,IE-HPLC测定结果与比较系统偏差>6%; 当HbF浓度达35.00%～70.00%时IE-HPLC无法检测出结果。免疫比浊法测定不同HbF浓度HbA1c值与比较系统偏差均<6%,测试几乎不受HbF的干扰。结论 HbF对不同HbA1c检测系统的干扰程度不同,临床实验室在进行HbA1c检测时,应注意血红蛋白变异体的存在,必要时选用替代指标或者合适的方法进行HbA1c测定以防止干扰的发生。     

糖耐量正常人群HbA1c分布特点及相关因素分析

目的分析糖化血红蛋白(Hb A1c)在糖耐量正常(NGT)人群中的分布特点及相关因素。方法选择北京市首钢四个社区糖尿病普查人群的资料,所有参加者进行人体学测量、75 g葡萄糖耐量试验(OGTT),同时检测Hb A1c、空腹血糖(FPG)、OGTT后2 h血糖值(2 h PG)及血生化。将9 711名符合入选标准的NGT人群的结果纳入分析,比较Hb A1c在不同性别及年龄组间(青年组、中年组、老年组及老老年组)的差异;根据Hb A1c水平分为≤5.6%、5.7%~6.4%和≥6.5%三组,比较三组的临床特点;采用Logistic回归方法分析与Hb A1c相关的因素。结果 (1)Hb A1c在NGT人群呈正态分布,平均(5.69±0.44)%,95%CI为4.83%~6.55%;男性与女性之间Hb A1c的水平有差异(P<0.05),尤其在老年组(60~79岁)差异显著(P<0.01)。(2)Hb A1c随着年龄的增加逐渐升高,Hb A1c、FPG及2 h PG在青年组(16~44岁)与中年组(45~59岁)间均有统计学差异(P<0.01);Hb A1c、FPG在青年组、中年组都与老年组(60~79岁)和老老年组(≥80岁)间有统计学差异(P<0.01),而2 h PG与老老年组无统计学差异;老年组和老老年组无统计学差异。(3)Hb A1c≤5.6%与Hb A1c 5.7%~6.4%和≥6.5%组之间在年龄、体质量指数(BMI)、腰臀比(WHR)、收缩压(SBP)、血胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)水平、FPG和2 h PG均有统计学差异(P<0.01或P<0.05);而Hb A1c 5.7%~6.4%与≥6.5%组之间比较差异均无统计学意义。(4)Logistic回归分析显示Hb A1c与性别、年龄、BMI、WHR、SBP、TC、FPG呈正相关,与DBP、HDL-C呈负相关。结论 NGT人群的Hb A1c随年龄的增长而升高,并与FPG呈正相关;处于高危Hb A1c范围的非糖尿病人群应加强对FPG、2 h PG和心血管危险因素的监测。     

VARIANTⅡ糖化血红蛋白分析仪检测HbA1c实验条件及影响因素探讨

目的探讨标本的存储条件、重度贫血、异常血红蛋白和仪器的维护保养等对VARIANTⅡ糖化血红蛋白分析仪HbA1c结果的影响进行探讨。方法选取20份EDTA抗凝血,按HbA1c低、中、高值进行混合,得到3份样本,分装后分别储存在室温18～26℃,2～8℃,-20℃左右3个温度条件下,从第1天到第7天对标本进行检测;选取20份重度贫血的患者标本分别作直接检测和稀释法测定;对含HbS/C/E/CHb/LA1c的标本进行检测;观察维护保养不到位对结果的影响。结果在室温下,HbA1c只能稳定4d,在2～8℃,-20℃左右下可以稳定7d;重度贫血对HbA1c的测定是有影响的,会使测定的结果偏低;一般的异常血红蛋白对结果无影响;分离柱和管路系统污染严重,血红蛋白各种组分的出峰时间会后移。结论标本的存储条件,重度贫血和仪器的维护保养不当对结果有影响,而一般的异常血红蛋白对结果无影响。     

HbA1c和HbA0的分离纯化

目的从健康人红细胞分离并纯化血红蛋白A1c（HbA1c）和血红蛋白A0（HbA0）。方法采集健康人全血,分离红细胞并制备溶血液,采用弱酸阳离子交换层析法分离HbA1c和HbA0,并用硼酸琼脂糖亲和层析法分别纯化。结果健康人红细胞溶血液采用弱酸阳离子交换层析法手工装柱分离提取HbA1c和HbA0峰值部分,高效液相色谱（HPLC）法测定纯度分别为79．78％和97．42％;再经硼酸琼脂糖亲和层析分别纯化,HbA1c纯度可达94．3％,HbA0纯度可达99．7％。结论单一的离子交换方法分离糖化Hb并不理想,必须与亲和层析结合,才能得到较高纯度HbA1c和HbA0。     

胱抑素C与HbA1c联合检测在糖尿病肾病中的应用

目的通过检测血清中的胱抑素C浓度和全血中糖化血红蛋白(HbA1c)浓度来判断糖尿病肾病的情况。方法分别检测40例健康者以及101例糖尿病患者的胱抑素C与HbA1c浓度。结果健康组胱抑素C与HbA1c均正常,而糖尿病组HbA1c与胱抑素C浓度则明显升高。而且HbA1c浓度越高,胱抑素C浓度也越高。结论糖尿病患者定期联合检测HbA1c及胱抑素C浓度有利于及时判断肾小球、肾小管的受损程度,且有利于临床医生及时采取相应的治疗措施。     

警惕糖化血红蛋白A1c在地中海贫血患者中误用

毛细管电泳法检测3例不同基因突变和缺失的地中海贫血患者结果显示3例患者Hb均异常,用阳离子交换高效液相色谱法(IE-HPLC)检测其糖化血红蛋白A1c(HbA1c)图谱均出现异常,而用硼酸盐亲和层析法、免疫比浊法检测结果均在仪器可报告范围内,但该结果并不能代表患者HbA1c水平。检测HbA1c时要了解患者的Hb是否存在异常,以避免指标误用。     

2型糖尿病患者左室整体舒缩功能与HbA1c的相关性研究

【目的】应用实时三平面定量组织速度成像技术（Triplane‐QTVI）评价2型糖尿病（T2DM）患者左室功能,并探讨T2DM患者左室功能与糖化血红蛋白（HbA1c）的相关性。【方法】选取单纯T2DM患者50例（T2DM组）和正常体检者50例（对照组）,采用常规超声心动图、Triplane‐QTVI技术检测左室纵轴收缩、舒张功能;检测T2DM患者的HbA1c ,并探讨超声心动图参数与 HbA1c的相关性。【结果】两组左室射血分数（EF％）、左室短轴缩短率（FS％）、二尖瓣环收缩期均值速度（Sm ）及二尖瓣口舒张早期最大血流速率（E ）比较无统计学意义（ P ＞0．05）;T2DM组左房收缩期最大血流速率（A）、二尖瓣环舒张晚期均值速度（Am）、E／二尖瓣环舒张早期均值速度（Em）高于对照组,E／A、Em、Em／Am明显低于对照组（ P ＜0．01）。HbA1c与E／A呈线形负相关（ P ＜0．05）,与E／Em呈线形正相关（ P＜0．05）,与EF、FS、E、A、Sm、Am不相关性。【结论】Triplane‐QTVI能够准确评价T2DM患者左室纵轴收缩、舒张功能,T2DM患者左室舒张功能障碍早于收缩功能,HbA1c与左室舒张功能障碍相关。     

Change in HbA1c concentration as decision parameter for frequency of HbA1c measurement

Abstract

Hemoglobin A_1c (HbA_1c) is a long-term measure for glucose concentration in plasma. Since its introduction as a diabetes monitoring tool, and its more recent application as a diagnostic tool, the number of measurements of HbA_1c have risen dramatically. However, HbA_1c change is slow, so repeating measurements should not be done too often. We use a large, unfiltered dataset from 52,017 patients to determine the possible rate of change in HbA_1c concentration. In our laboratory, the critical difference between HbA_1c measurements is 8.5%. Our data show that a 1-unit HbA_1c rise takes 4 weeks to occur, hence, at a HbA_1c concentration around 50?mmol/mol Hgb, a critically increased HbA_1c concentration cannot be determined until after 16 weeks. Conversely a critically lower HbA1c can manifest itself after 2 weeks, but after 7 weeks the dropping tendency stops. The amount of measurements that can be cancelled because they were taken sooner than 16 weeks is 23 percent.     

Immediate HbA1c results. Performance of new HbA1c system in pediatric outpatient population.

OBJECTIVE--This study compared the performance of a new device that uses an IA to measure HbA1c in 9 min with a 1-microliter capillary blood sample with AC and CE methods in both nondiabetic and diabetic pediatric patients. RESEARCH DESIGN AND METHODS--Two hundred seven pediatric subjects (103 nondiabetic, 104 with insulin-dependent diabetes mellitus) had HbA1c measured with the IA method and compared with total GHb values determined by AC and HbA1 by the CE method with the same whole-blood capillary aliquot. Glucose values were also obtained from the same blood samples. RESULTS--Correlations and regression analyses show excellent correspondence between the three assays. The correlation between the AC and CE methods is 0.98 (P less than 0.001) with a slope of 1.615 +/- 0.0125 and intercept of 4.00 +/- 0.20. The correlation between the IA and AC methods is 0.99 (P less than 0.001) with a slope of 0.608 +/- 0.007 and intercept of 1.326 +/- 0.066. The correlation between the IA and CE methods is 0.97 (P less than 0.001), with a slope of 0.983 +/- 0.018 and intercept of 1.122 +/- 0.153. The average difference and average percentage difference between methods were also significant (P less than 0.001), reflecting the differences in GHb components measured. There was a significant correlation (P less than 0.001) between each method and glucose values (IA r = 0.72, AC r = 0.70, CE r = 0.73). Within-run precision for IA ranged from 1.7 to 3.5% and between-run precision 2.7 to 4.1%. CONCLUSIONS--Study results suggest that the IA method gives extremely accurate and reliable values over the clinical range of interest. The instrument is small, portable, easy to use, and provides information within 9 min for both physicians and patients.     

QA aspects for HbA1c measurements

OBJECTIVES: To provide mechanisms for evaluating HbA(1c) results that meet the criteria for review by the 2002 NACB guidelines for reporting HbA(1c) values. DESIGN AND METHODS: Complete blood count (CBC) data and comparison of obtained HbA(1c) with a calculated HbA(1c) were used to assess the validity of HbA(1c) results meeting the NACB review criteria. RESULTS: The use of CBC data and a calculated HbA(1c) were found to be useful in evaluating the validity of unusual HbA(1c) results. CONCLUSIONS: The validity of high and low HbA(1c) results can be checked by the review of CBC data and comparing a calculated HbA(1c) against the measured value.