Alberta Precision Laboratories, Diagnostic and Scientific Research Centre, #9 3535 Research Way NW, Calgary, AB T2L 2K8, Canada; Departments of Pathology and Laboratory Medicine, Cumming School of Medicine, Health Sciences Centre, Foothills Campus, University of Calgary, 3030 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
Alberta Precision Laboratories, Diagnostic and Scientific Research Centre, #9 3535 Research Way NW, Calgary, AB T2L 2K8, Canada; Departments of Pathology and Laboratory Medicine, Cumming School of Medicine, Health Sciences Centre, Foothills Campus, University of Calgary, 3030 Hospital Drive NW, Calgary, AB T2N 4N1, Canada; Department of Cardiac Sciences, Cumming School of Medicine, Health Sciences Centre, Foothills Campus, University of Calgary, 3030 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
Clin Biochem. 2024 Dec;133-134:110831. doi: 10.1016/j.clinbiochem.2024.110831. Epub 2024 Sep 30.
Exposing blood specimens to air reduces plasma total carbon dioxide (TCO). We evaluated the degree of TCO reduction attributed to open collection of neonatal blood in BD microtainers® (microtainers), microtainer transport duration and delayed testing of open plasma aliquots.
Venous blood was aliquoted into open microtainers in a 3x4 factorial design to simulate combined effects of blood volume (0.2-0.6 mL) and air exposure duration (0-5 min), with blood drawn in vacutainers as a control. Separate effects of in-hospital transport duration (0-120 min; whole blood), off-site transport duration (0-24 h; centrifuged whole blood), and the duration plasma aliquots remained open (0-120 min) were evaluated by repeated testing. Findings were analyzed using repeated-measures ANOVA and Student's T-tests.
In the factorial experiment, mean plasma TCO in microtainers was on average 3.5 mmol/L lower than in vacutainers. Smaller blood volume but not greater air exposure duration significantly (p < 0.05) reduced TCO. Mean TCO in filled (0.6 mL; 1-5 min air exposure) microtainers was on average 2.9 mmol/L lower than in vacutainers. Simulated off-site transport of microtainers containing centrifuged whole blood significantly reduced TCO (4 h; mean change = -1.5 mmol/L), as did delayed testing of aliquoted plasma (15 min; mean change = -1.3 mmol/L).
Plasma TCO decreased with reduced microtainer blood volume, extended off-site transport duration of centrifuged whole blood and testing delay of aliquoted plasma. To minimize TCO reduction, microtainers should be fully filled and tested rapidly. Laboratories should also consider whether an interpretive comment, correction factor or separate reference intervals are appropriate for these tests.
将血标本暴露于空气中会降低血浆总二氧化碳（TCO）。我们评估了在 BD microtainers®（microtainers）中开放式采集新生儿血液、microtainer 运输时间以及延迟检测开放式血浆等分试样对 TCO 降低的影响程度。
采用 3x4 析因设计，将静脉血分入开放式 microtainers 中，模拟血液量（0.2-0.6 mL）和空气暴露时间（0-5 分钟）的综合影响，同时以 vacutainers 采血作为对照。通过重复检测，评估了医院内运输时间（0-120 分钟；全血）、院外运输时间（0-24 小时；离心全血）以及血浆等分试样暴露时间（0-120 分钟）对 TCO 的单独影响。使用重复测量方差分析和学生 T 检验对结果进行分析。
在析因实验中，microtainers 中的平均血浆 TCO 比 vacutainers 低 3.5 mmol/L。较小的血液量而不是更大的空气暴露时间显著（p < 0.05）降低了 TCO。充满（0.6 mL；1-5 分钟空气暴露）microtainers 中的平均 TCO 比 vacutainers 低 2.9 mmol/L。含有离心全血的 microtainers 的院外运输显著降低了 TCO（4 小时；平均变化=-1.5 mmol/L），延迟检测等分试样血浆也降低了 TCO（15 分钟；平均变化=-1.3 mmol/L）。
随着 microtainer 血液量减少、离心全血的院外运输时间延长以及血浆等分试样的检测延迟，血浆 TCO 降低。为了最大程度减少 TCO 降低，microtainers 应完全装满并快速检测。实验室还应考虑是否需要对这些检测进行解释性注释、校正因子或单独的参考区间。
