Direct enzymatic assay for %HbA1c in human whole blood samples

ObjectivesDevelopment and validation of a direct enzymatic HbA1c assay that utilizes a single channel on chemistry auto-analyzers without the need to run separate glycated hemoglobin and total hemoglobin assays.Design and methodsAn enzyme based single channel assay was developed to measure %HbA1c in human whole blood samples. The performance characteristics of the Diazyme Direct Enzymatic HbA1c Assay were evaluated on the Hitachi 917 auto-analyzer using whole blood samples, appropriate controls and a reference lot of manufactured reagents. Accuracy studies were completed by comparing the Direct Enzymatic Assay to existing HPLC and immunoassay methods. Interference testing was performed to determine the effect of total hemoglobin, glycated serum proteins, chemical substances and hemoglobin variants in patient samples.ResultsThe Direct Enzymatic HbA1c Assay showed within run precision and total precision results of ≤ 2% CV for both normal and abnormal level samples. Method comparison studies showed that there was a good correlation between the Direct Enzymatic HbA1c and the HPLC (R² = 0.98) or the immunoassay (R² = 0.97) methods. The assay measured within the range of 4–16% HbA1c and showed excellent performance with variant hemoglobin in samples.ConclusionsDiazyme Direct Enzymatic HbA1c Assay is accurate and precise when compared to currently marketed medical devices. The assay is designed to report %HbA1c values directly without need for a separate measurement of total hemoglobin and is not adversely affected by interferences from common hemoglobin variants in samples. It is a cost effective, user-friendly method and is adaptable to most general chemistry analyzers.     

空腹血糖联合糖化血红蛋白检测对糖尿病筛查的临床意义

目的评价联合应用空腹血糖和糖化血红蛋白(HbA1c)检测对糖尿病筛查的临床价值。方法对8669名特定人群,同时进行空腹血糖和糖化血红蛋白(HbA1c)检测,所得数据进行对比分析。结果单独以空腹血糖大于等于6.1mmol/L筛查出的糖尿病风险人群为743人,占总检测人数的8.6%;单独以糖化血红蛋白(HbA1c)大于等于6%筛查出的糖尿病风险人群为627人,占总检测人数的7.2%;联合两种检测进行筛查,以两个指标中任何一个超过切点的都筛出来,可筛查出943人,风险筛出率为10.9%;通过统计学分析,差异有统计学意义(P﹤0.01)。结论空腹血糖或糖化血红蛋白(HbA1c)单个指标进行糖尿病风险筛查,都会有一部分可疑人群无法筛出,二者联合应用,可以筛查出更多处于糖尿病风险的可疑人群。     

Hemolysis causes a decrease in HbA1c level but not in glycated albumin or 1,5-anhydroglucitol level

HbA1c has been widely used as a glycemic control indicator or as a diagnostic indicator for diabetes mellitus. However, HbA1c is affected by the erythrocyte life span and, therefore, shows falsely low values in hemolytic patients. Erythrocyte creatine (EC) is a sensitive hemolytic marker that reflects the mean erythrocyte age. In the present study, the relationships of HbA1c, glycated albumin (GA), and 1,5-anhydroglucitol (1,5-AG) with different hemolytic markers, including EC, were investigated in non-diabetic individuals. A total of 43 non-diabetic individuals whose complete blood count and reticulocytes were measured via medical examinations were included in this study (28 individuals with hemolysis and 15 individuals without hemolysis). Those with suspected diabetes mellitus based on medical history, low 1,5-AG values, or had comorbid liver and renal diseases were excluded from this study. HbA1c, GA, 1,5-AG, and various hemolytic markers were measured to examine the correlation of the glycemic control indicators with the various hemolytic markers. A significant correlation was observed between GA and 1,5-AG but not between HbA1c and GA or 1,5-AG. Significant correlations were observed between HbA1c values and various hemolytic markers (reticulocytes, haptoglobin, and EC) but not between GA or 1,5-AG values and those hemolytic markers. HbA1c, but not with GA and 1,5-AG, showed significant correlations with the hemolytic markers. These results suggested that HbA1c does not reflect the glycemic control accurately in hemolytic patients, while GA and 1,5-AG values are not affected by mean erythrocyte age and, therefore, accurately reflect the glycemic control.     

酶化学法测定糖化血红蛋白性能的验证

目的对酶化学法测定糖化血红蛋白进行方法学性能的验证。方法参考美国国家临床实验室标准化委员会系列文件和相关文献,结合工作实际对酶化学法测定糖化血红蛋白进行精密度、准确度的分析测量范围和生物参考区间等进行评价,并将实验结果与厂家提供的分析性能或公认的质量指标进行比较。结果批内变异系数(CV)0.87%~1.29%,批间CV1.74%~2.12%;在3.0%~16.0%范围内线性良好Y=1.010X-0.004,r=0.999 7,平均回收率101.37%;该方法与TOSOH G7离子交换高效液相层析法二组比较差异无统计学意义(Y=0.962 2X+0.045,r=0.994 0,P>0.05);分析测量范围(AMR)验证和生物参考区间验证结果均符合质量要求。结论酶化学法测定糖化血红蛋白主要分析性能符合质量目标要求,适合临床检验科应用。     

两种方法检测糖化血红蛋白比较分析

目的对免疫比浊法与高效液相色谱法(HPLC)检测糖化血红蛋白进行方法学比较。方法采用免疫比浊法与高效液相色谱法测定100例糖尿病患者糖化血红蛋白,分别进行精密度、线性范围及相关性分析。结果免疫比浊法与HPLC法的线性范围分别为3.1%～14.8%和4.0%～18.1%,批内、批间变异系数(CV)均小于5%,两种方法测定糖化血红蛋白的结果差异无统计学意义(P>0.05),相关性好,回归方程为Y=1.016 X+0.336%(r=0.977 8)。结论两种检测方法均能较好地满足临床需求。     

Evaluation of HbA1c on the Roche COBAS Integra 800 closed tube system

OBJECTIVES: Evaluate a new whole blood (WB) HbA1c immunoassay and system with closed tube sampling (CTS) capability. DESIGN AND METHODS: Compare the Tina-quant Haemoglobin A1c Gen.2 (A1C-2) application on the COBAS INTEGRA 800 (I800) and new I800 dedicated system with CTS capability to current Integra applications and a HbA1c method accurate with common haemoglobin (Hb) variants. RESULTS: CVs were < or =1.7%. Mean bias against National Glycohaemoglobin Standardization Program (NGSP) samples was 0.3 HbA1c %. Compared to the Hitachi Tina-quant(R) [a] HbA1c II (HbA1c II) assay (accurate with common Hb variants), mean bias was 0.04% and 0.21% HbA1c at 6% and 9%, respectively, with Hb AS variants; and -0.01% and 0.26% HbA1c at 6% and 9%, respectively, with Hb AC variants. CONCLUSIONS: The Integra A1C-2 application is precise, accurate against NGSP-assigned samples and the Hb variants tested; and, the I800 dedicated system with CTS capability offers increased throughput and reduced sample handling.     

糖化血红蛋白与活化部分凝血活酶时间的相关性研究

目的 研究糖化血红蛋白(HbA1c)与活化部分凝血活酶时间的相关性,评价2型糖尿病的凝血功能.方法 收集符合标准的病例200例,HbA1c<6.2% 121例,HbA1c>6.2% 79例,分别进行凝血酶原时间(PT)、部分凝血活酶时间(APTT)、纤维蛋白原(FIB)、凝血酶时间(TT)项目的 测试.结果 组内比较:HbA1c <6.2%组,FIB升高差异有统计学意义(P<0.01),说明控制较好的糖尿病患者多伴有FIB升高;HbA1c >6.2 g/L组,APTT缩短,FIB升高差异有统计学意义(P<0.01);说明控制较差的患者常伴有APTT缩短,FIB升高.两组间APTT缩短差异有统计学意义,说明APTT缩短与HbA1c呈正相关.结论 APTT可作为2型糖尿病凝血功能的评价指标.     

Analysis of HbA1c on an automated multicapillary zone electrophoresis system

Hemoglobin A1c (HbA1c) is a frequently requested laboratory test and there is thus a need for high throughput instruments for this assay. We evaluated a new automated multicapillary zone electrophoresis instrument (Capillarys 3 Tera, Sebia, Lisses, France) for analysis of HbA1c in venous samples. Routine requested HbA1c samples were analyzed immunologically on a Roche c6000 instrument (n?=?142) and then with the Capillarys 3 Tera instrument. The Capillarys 3 Tera instrument performed approximately 70 HbA1c tests/hour. There was a strong linear correlation between Capillarys 3 Tera and Roche Tina-Quant HbA1c Gen 3 assay (y?=?1.003x – 0.3246 R^2?=?.996). The total CV for the 12 capillaries varied between 0.8 and 2.2% and there was a good agreement between duplicate samples (R^2?=?.997). In conclusion, the Capillarys 3 Tera instrument has a high assay capacity for HbA1c. It has a good precision and agreement with the Roche Tina-Quant HbA1c method and is well suited for high volume testing of HbA1c.     

Can the Afinion HbA1c Point-of-Care instrument be an alternative method for the Tosoh G8 in the case of Hb-Tacoma?

Background: Hb-variant interference when reporting HbA1c has been an ongoing challenge since HbA1c was introduced to monitor patients with diabetes mellitus. Most Hb-variants show an abnormal chromatogram when cation-exchange HPLC is used for the determination of HbA1c. Unfortunately, the Tosoh G8 generates what appears to be normal chromatogram in the presence of Hb-Tacoma, yielding a falsely high HbA1c value. The primary aim of the study was to investigate if the Afinion HbA1c point-of-care (POC) instrument could be used as an alternative method for the Tosoh G8 when testing for HbA1c in the presence of Hb-Tacoma.

Methods: Whole blood samples were collected in K₂EDTA tubes from individuals homozygous for HbA (n?=?40) and heterozygous for Hb-Tacoma (n?=?20). Samples were then immediately analyzed with the Afinion POC instrument. After analysis, aliquots of each sample were frozen at ?80?°C. The frozen samples were shipped on dry ice to the European Reference Laboratory for Glycohemoglobin (ERL) and analyzed with three International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and National Glycohemoglobin Standardization Program (NGSP) Secondary Reference Measurement Procedures (SRMPs). The Premier Hb9210 was used as the reference method.

Results: When compared to the reference method, samples with Hb-Tacoma yielded mean relative differences of 31.8% on the Tosoh G8, 21.5% on the Roche Tina-quant Gen. 2 and 16.8% on the Afinion. Conclusions: The Afinion cannot be used as an alternative method for the Tosoh G8 when testing for HbA1c in the presence of Hb-Tacoma.     

老年糖尿病人群HbA_(1c)水平对心血管疾病的预测作用

目的观察老年糖尿病人群糖化血红蛋白(HbA_(1c))水平,探讨其与合并心血管疾病的相关性。方法以220例老年2型糖尿病患者为糖尿病组,214例非糖尿病老年患者为对照组,比较2组患者空腹静脉血血糖、糖化血红蛋白、甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)含量。将220例糖尿病患者分为非冠心病组和冠心病组,比较2组HbA_(1c)含量。分析HbA_(1c)水平与收缩压、舒张压以及超敏C反应蛋白(Hs-CRP)水平的相关性。结果糖尿病组收缩压、舒张压、血糖相关指标(FPG、FINS)、Hs-CRP、HbA_(1c)水平均显著高于非糖尿病组(P0.001),HDL-C水平显著低于非糖尿病组(P0.001);冠心病组HbA_(1c)水平显著高于非冠心病组(P0.001);老年糖尿病患者血清HbA_(1c)水平与SBP、DBP和Hs-CRP水平均呈正相关。结论老年糖尿病人群HbA_(1c)水平对心血管疾病具有一定的预测作用。     

非糖尿病冠心病患者糖化血红蛋白的临床价值

目的:探讨非糖尿病冠心病患者的糖化血红蛋白水平及与冠状动脉病变程度的关系。方法:对非糖尿病患者根据冠状动脉造影结果分为对照组、单支病变组、多支病变组。所有研究对象检测糖化血红蛋白,空腹血糖、餐后2 h血糖、血脂、肝肾功能。结果:正常对照组、冠状动脉单支血管病变组、冠状动脉多支血管病变组的糖化血红蛋白分别为(5.38±0.39)%,(5.69±0.40)%,(5.98±0.41)%,糖化血红蛋白随着病变血管数的增加而升高。显示糖化血红蛋白与非糖尿病冠心病患者冠状动脉病变程度密切相关(r=0.42,P<0.05)。结论:糖化血红蛋白与非糖尿病冠心病患者动脉粥样硬化严重程度呈正相关,对冠状动脉病变严重程度预测价值高于空腹血糖及餐后2 h血糖。     

HLC-723 G7糖化血红蛋白分析仪性能的评价及其在糖尿病筛查的应用

目的评价HLC-723 G7糖化血红蛋白分析仪的临床应用性能,并建立深圳地区健康人群糖化血红蛋白（HbA1c）的参考区间及用于糖尿病筛查的＂cut-off＂值。方法对HLC-723 G7测定HbA1c的精密度、准确度、线性、携带污染进行评价;并检测482例健康体检者和150例糖尿病患者HbA1c。结果HLC-723 G7测定HbA1c高、低两水平批内精密度的CV分别为0.69%、0.94%,总精密度的CV分别为1.25%、1.79%;HLC-723 G7与VARIANTⅡ测定HbA1c结果呈明显相关（r=0.996,Sy.x=0.28,P〈0.001）,在6.0%、7.0%、9.0%的相对偏倚分别为-0.40%-、0.14%、0.20%;HLC-723 G7测定HbA1c在3.1%-15.9%范围内线性良好（r=0.999,P〈0.001）,高值标本对低值标本的测定结果无明显携带污染;深圳地区健康人群HbA1c总体参考区间为4.5%-6.1%;HbA1c用于糖尿病筛查受试者工作（ROC）曲线下面积为0.934,＂cut-off＂值5.9%处灵敏度为82.0%,特异性为91.3%。结论HLC-723 G7糖化血红蛋白分析仪测定HbA1c性能良好,可用于糖尿病的早期筛查。     

糖化血红蛋白及糖化白蛋白在妊娠期糖尿病初筛中的价值

目的探讨糖化白蛋白(GA)和糖化血红蛋白(Hb A1c)检测在妊娠期糖尿病(GDM)筛查中的价值。方法选取妊娠22~28周的孕妇289例,其中血糖正常组202例、GDM组87例。分别采用己糖激酶法检测血糖、高压液相层析法检测Hb A1c,酶法检测GA。结果 GDM组Hb A1c为(5.20%±0.09%),明显高于血糖正常组(5.03%±0.02%,P0.01);GA为13.48%±0.28%,与血糖正常组(13.39%±0.09%)比较差异无统计学意义(P0.05)。Pearson相关分析显示血糖与Hb A1c呈正相关(r=0.203,P0.01),血糖与GA无相关性(r=0.114,P0.05),Hb A1c与GA无相关性(r=0.041,P0.05)。以血糖正常组Hb A1c第95%位值(5.50%)作为判断依据筛查GDM,特异性为94.55%,敏感性为86.21%。结论 Hb A1c相对于GA而言,是筛查GDM更好的指标。     

糖化血红蛋白及糖化白蛋白在妊娠期糖尿病诊断中的价值

目的评估糖化血红蛋白(HbA1c)和血清糖化白蛋白(GA)在妊娠期糖尿病(GDM)患者早期监测中的作用。方法根据美国糖尿病协会(ADA)建议,以口服75 g葡萄糖耐量试验(OGTT)测定值作为诊断GDM的标准,将98例妊娠妇女(孕期22~24周)分为正常妊娠组50例、GDM组48例,同时测定2组的HbA1c和GA,并进行统计学分析及受试者工作特征(ROC)曲线分析。结果 GDM组的HbA1c和GA明显高于正常妊娠组(P0.01)。当HbA1c的Cut-off值为5.15%时,ROC曲线下面积为0.954±0.020,敏感性为87.5%,特异性为92.0%。当GA的Cut-off值12.50%时,ROC曲线下面积为0.910±0.029,敏感性为81.3%,特异性为84.0%。HbA1c和GA联合诊断GDM的敏感性为70.8%、特异性为98.0%。结论当HbA1c5.15%和GA12.50%时,诊断GDM的敏感度和特异性较高。HbA1c和GA联合检测对GDM有重要价值。