Department of Biochemistry, Faculty of Medicine, Zonguldak Bülent Ecevit University, Zonguldak, Turkey.
Biochem Med (Zagreb). 2023 Feb 15;33(1):010901. doi: 10.11613/BM.2023.010901.
Blood samples having inappropriate volume are a substantial part of preanalytical errors. Inadequate sample volume for glycated haemoglobin (HbA1c) test may be a common problem of patients with diabetes mellitus having vascular changes. In this study, we compared HbA1c concentrations of underfilled and appropriately filled blood collection tubes.
To compare HbA1c concentrations, blood samples were collected into 2 mL tubes containing K3-EDTA from 109 subjects. Two blood samples (underfilled and appropriately filled) were drawn from a patient by the same personnel and materials. HbA1c measurements were assayed on a Cobas 6000 analyser module c 501 (Roche Diagnostics, Mannheim, Germany). The HbA1c% results were compared by t-test and Wilcoxon's signed-rank statistical methods (SPSS Inc., Chicago, USA). Bias analysis was performed using Microsoft Excel 4.0.
Underfilled samples were classified three groups (group 1, N = 44; group 2, N = 36; and group 3, N = 29) according to the filling ratio of the samples; 0.5 mL and below (< 25%), 0.5-1.0 mL (25-50%), and 1.0-2.0 mL (> 50%), respectively. When we compared underfilled tubes with pairing filled tubes, there was a statistically significant difference only with tubes filled less than 25% (P = 0.030). Furthermore, we have done bias analysis between paired tubes according to the diagnostic cut-off value of 6.5%. The bias was more prominent in up to 50% underfilled blood tubes (1.1%), when HbA1c concentrations were below the diagnostic cut-off of 6.5%.
We suggest that the blood tubes with EDTA for HbA1c measurement should be filled with at least 50% to avoid clinical variations.
血量不足的血样是分析前误差的主要部分。对于伴有血管病变的糖尿病患者，糖化血红蛋白（HbA1c）检测的样本量不足可能是一个常见问题。在本研究中，我们比较了填充不足和适当填充的血液采集管的 HbA1c 浓度。
为了比较 HbA1c 浓度，从 109 名患者中采集了含有 K3-EDTA 的 2mL 管中的血液样本。同一名医务人员和材料从每位患者中抽取了两份血液样本（填充不足和适当填充）。在 Cobas 6000 分析仪模块 c 501（罗氏诊断公司，曼海姆，德国）上测定 HbA1c 测量值。使用 t 检验和 Wilcoxon 符号秩统计方法（SPSS Inc.，芝加哥，美国）比较 HbA1c%结果。使用 Microsoft Excel 4.0 进行偏差分析。
根据样本的填充率，将填充不足的样本分为三组（组 1，N=44；组 2，N=36；组 3，N=29）；分别为 0.5mL 及以下（<25%）、0.5-1.0mL（25-50%）和 1.0-2.0mL（>50%）。当我们将填充不足的管与配对填充的管进行比较时，只有填充量小于 25%的管之间存在统计学显著差异（P=0.030）。此外，我们根据 6.5%的诊断截止值对配对管进行了偏差分析。当 HbA1c 浓度低于 6.5%的诊断截止值时，在填充量不足 50%的血液管中，偏差更为明显（1.1%）。
我们建议，用于 HbA1c 测量的 EDTA 血液管应至少填充 50%，以避免临床变化。
