Herman William H, Fajans Stefan S
Department of Internal Medicine, University of Michigan, Michigan, USA.
Pol Arch Med Wewn. 2010;120(1-2):37-40.
The International Expert Committee recommends that the diagnosis of diabetes be made if hemo globin A1c (HbA1c) level is greater, similar 6.5% and confirmed with a repeat HbA1c test. The committee recommends against "mixing different methods to diagnose diabetes" because "the tests are not completely concordant: using different tests could easily lead to confusion". Fasting plasma glucose, 2-hour postglucose-load plasma glucose, and oral glucose tolerance tests are recommended for the diagnosis of diabetes only if HbA1c testing is not possible due to unavailability of the assay, patient factors that preclude its inter pretation, and during pregnancy. HbA1c testing has the advantages of greater clinical convenience, preanalytic stability, and assay standardization, but when used as the sole diagnostic criterion for diabetes, it has the potential for systematic error. Factors that may not be clinically evident impact HbA1c test results and may systematically raise or lower the value relative to the true level of glycemia. For this reason, HbA1c should be used in combination with plasma glucose determinations for the diagnosis of diabetes. If an HbA1c test result is discordant with the clinical picture or equivocal, plasma glucose testing should be performed. A diagnostic cut-off point of HbA1c greater, similar 6.5% misses a substantial number of people with type 2 diabetes, including some with fasting hyperglycemia, and misses most people with impaired glucose tolerance. Combining the use of HbA1c and plasma glucose measurements for the diagnosis of diabetes offers the benefits of each test and reduces the risk of systematic bias inherent in HbA1c testing alone.
国际专家委员会建议，如果糖化血红蛋白（HbA1c）水平大于或等于6.5%，则应诊断为糖尿病，并通过重复的HbA1c检测进行确认。该委员会不建议“混合使用不同方法诊断糖尿病”，因为“这些检测方法并不完全一致：使用不同检测方法很容易导致混淆”。仅在由于检测方法不可用、患者因素妨碍其解读以及在怀孕期间无法进行HbA1c检测时，才建议使用空腹血糖、葡萄糖负荷后2小时血糖和口服葡萄糖耐量试验来诊断糖尿病。HbA1c检测具有临床便利性更高、分析前稳定性更好以及检测标准化等优点，但当用作糖尿病的唯一诊断标准时，它存在系统误差的可能性。一些临床上可能不明显的因素会影响HbA1c检测结果，并可能相对于真正的血糖水平系统性地升高或降低该值。因此，HbA1c应与血浆葡萄糖测定结合使用以诊断糖尿病。如果HbA1c检测结果与临床表现不一致或不明确，则应进行血浆葡萄糖检测。HbA1c大于或等于6.5%的诊断切点会遗漏大量2型糖尿病患者，包括一些空腹血糖升高的患者，并且会遗漏大多数糖耐量受损的患者。联合使用HbA1c和血浆葡萄糖测量来诊断糖尿病可发挥每种检测方法的优势，并降低仅使用HbA1c检测时固有的系统偏差风险。
