Carey Rebekah, Lunt Helen, Heenan Helen F, Frampton Christopher M A, Florkowski Christopher M
School of Medicine, University of Otago Christchurch, Christchurch, New Zealand.
Diabetes Centre, Christchurch Hospital, Christchurch, New Zealand; Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand.
Clin Biochem. 2016 Dec;49(18):1406-1411. doi: 10.1016/j.clinbiochem.2016.05.017. Epub 2016 May 24.
Blood collection tubes containing citrate lower pH, thereby inhibiting glycolysis. When compared to other additives, they introduce an over-estimation in measured glucose. This study explored this over-estimation across a range of glucose values. Blood samples collected into lithium-heparin tubes then cooled prior to immediate refrigerated plasma separation, were used as the primary comparator.
Venous blood from individuals with and without diabetes was collected into tubes containing lithium-heparin, or fluoride, or fluoride-citrate (Terumo™ Venosafe). Plasma was separated at time intervals of zero, 2 and 24h. Preparation of the 'time zero' lithium-heparin and fluoride samples was optimised by processing these samples under cooled conditions. The remaining samples were prepared at room temperature. Plasma was analysed in the routine clinical laboratory using the hexokinase method.
Median plasma glucose for the 50 participants was 7.1mmol/L (range 3.1-21.5). At 'time zero', fluoride-citrate glucose was 0.37mmol/L (95% CI 0.26-0.48) higher than lithium-heparin glucose and 0.29mmol/L (95% CI 0.21-0.36) higher than glucose from fluoride tubes. Following delayed plasma separation at 24h, glucose loss from the lithium heparin tubes averaged 0.2mmol·L·hr. In contrast, the fluoride-citrate tubes showed minimal glucose loss over 24h.
Acid stabilises glycolysis but causes an over-estimation in glucose, across a range of plasma glucose values, when compared to blood collected into conventional tubes under cooled conditions. The magnitude of the over-estimation seen with the fluoride-citrate tubes is unlikely to be due solely to the differential glucose stabilisation rates of acid, compared to cooling.
含有柠檬酸盐的采血管会降低pH值，从而抑制糖酵解。与其他添加剂相比，它们会导致测得的葡萄糖值被高估。本研究探讨了在一系列葡萄糖值范围内的这种高估情况。将采集到锂肝素管中然后在立即进行冷藏血浆分离之前冷却的血样用作主要对照。
将患有和未患有糖尿病的个体的静脉血采集到含有锂肝素、氟化物或氟化物-柠檬酸盐（Terumo™ Venosafe）的试管中。在0、2和24小时的时间间隔分离血浆。通过在冷却条件下处理这些样品来优化“零时间”锂肝素和氟化物样品的制备。其余样品在室温下制备。使用己糖激酶法在常规临床实验室中分析血浆。
50名参与者的血浆葡萄糖中位数为7.1mmol/L（范围3.1-21.5）。在“零时间”，氟化物-柠檬酸盐葡萄糖比锂肝素葡萄糖高0.37mmol/L（95%可信区间0.26-0.48），比氟化物管中的葡萄糖高0.29mmol/L（95%可信区间0.21-0.36）。在24小时延迟血浆分离后，锂肝素管中的葡萄糖损失平均为0.2mmol·L·hr。相比之下，氟化物-柠檬酸盐管在24小时内显示出最小的葡萄糖损失。
与在冷却条件下采集到传统试管中的血液相比，酸可稳定糖酵解，但在一系列血浆葡萄糖值范围内会导致葡萄糖被高估。氟化物-柠檬酸盐管中观察到的高估幅度不太可能仅归因于与冷却相比酸的葡萄糖稳定率差异。
