Schnedl Wolfgang J, Lahousen Theresa, Krause Robert, Wallner Sandra J, Piswanger-Soelkner Claudia, Lipp Rainer W
Dept. of Internal Medicine, Medical University of Graz, Graz, Austria.
Clin Lab. 2007;53(3-4):179-81.
Evaluation of conditions associated with glycated hemoglobin (HbA1c) values below the reference range in HbA1c determinations.
Over a time period of 5 years, HbA1c results were determined with the ion-exchange high-performance liquid chromatography (HPLC) method HA-8140 Menarini.
Of approximately 20 000 HbA1c results analyzed, 9 were below the reference range. The reason for HbA1c values below the reference range was found to be liver cirrhosis in 6 patients, anemia with hematological neoplasms in 2 patients, and elevated fetal hemoglobin > 1.5% in one patient. The silent hemoglobin (Hb) variant Hb Graz in 6 patients, Hb Sherwood Forest in 1 patient, homozygote HbS in one patient, and gross hypertriglyceridemia in one patient demonstrated no HbA1c result.
In patients with liver cirrhosis, HbA1c measurements should be used with caution when evaluating long-term glucose control, and samples with suspected Hb variants should be analyzed by hemoglobin electrophoresis. Our study underscores the need for clinical laboratories and physicians to be aware of the limitations of their HbA1c assay methods as well as of the importance of visual inspection of ion-exchange chromatograms to detect HbA1c values below the reference range and abnormalities caused by the interference factors described here.
评估糖化血红蛋白（HbA1c）测定值低于参考范围的相关情况。
在5年的时间里，采用Menarini HA - 8140离子交换高效液相色谱（HPLC）法测定HbA1c结果。
在分析的约20000份HbA1c结果中，有9份低于参考范围。发现HbA1c值低于参考范围的原因是6例患者为肝硬化，2例患者为血液系统肿瘤伴贫血，1例患者胎儿血红蛋白升高>1.5%。6例患者存在沉默血红蛋白（Hb）变异体Hb Graz，1例患者存在Hb Sherwood Forest，1例患者为纯合子HbS，1例患者存在严重高甘油三酯血症，均未得出HbA1c结果。
对于肝硬化患者，在评估长期血糖控制时应谨慎使用HbA1c测量值，对于疑似存在Hb变异体的样本应通过血红蛋白电泳进行分析。我们的研究强调临床实验室和医生需要意识到其HbA1c检测方法的局限性，以及目视检查离子交换色谱图以检测低于参考范围的HbA1c值和此处所述干扰因素引起的异常情况的重要性。
