Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Verona, Italy.
Biochem Med (Zagreb). 2013;23(2):218-23. doi: 10.11613/bm.2013.026.
Procedures involving phlebotomy are critical for obtaining diagnostic blood specimens and represent a well known and recognized problem, probably among the most important issues in laboratory medicine. The aim of this report is to show spurious hyperkalemia and hypocalcemia due to inadequate phlebotomy procedure. The diagnostic blood specimens were collected from a male outpatient 45 years old, with no clinical complaints. The tubes drawing order were as follows: i) clot activator and gel separator (serum vacuum tube), ii) K,EDTA, iii) a needleless blood gas dedicated-syringe with 80 I.U. lithium heparin, directly connected to the vacuum tube holder system. The laboratory testing results from serum vacuum tube and dedicated syringe were 4.8 and 8.5 mmol/L for potassium, 2.36 and 1.48 mmol/L for total calcium, respectively. Moreover 0.15 mmol/L of free calcium was observed in dedicated syringe. A new blood collection was performed without K3EDTA tube. Different results were found for potassium (4.7 and 4.5 mmol/L) and total calcium (2.37 and 2.38 mmol/L) from serum vacuum tube and dedicated syringe, respectively. Also free calcium showed different concentration (1.21 mmol/L) in this new sample when compared with the first blood specimen. Based on this case we do not encourage the laboratory managers training the phlebotomists to insert the dedicated syringes in needle-holder system at the end of all vacuum tubes. To avoid double vein puncture the dedicated syringe for free calcium determination should be inserted immediately after serum tubes before EDTA vacuum tubes.
涉及采血的程序对于获取诊断性血液标本至关重要,这是一个众所周知且公认的问题,可能是实验室医学中最重要的问题之一。本报告的目的是展示由于采血程序不当导致的假性高钾血症和低钙血症。诊断性血液标本取自一名 45 岁的男性门诊患者,无临床症状。采血管的抽取顺序如下:i)凝血激活剂和凝胶分离器(血清真空采血管),ii)K、EDTA,iii)带 80I.U.肝素锂的无针血气专用注射器,直接连接到真空采血管架系统。血清真空采血管和专用注射器的实验室检测结果分别为钾 4.8mmol/L 和 8.5mmol/L,总钙 2.36mmol/L 和 1.48mmol/L,专用注射器中还观察到游离钙 0.15mmol/L。重新采集不含 K3EDTA 管的血液。血清真空采血管和专用注射器的钾(4.7mmol/L 和 4.5mmol/L)和总钙(2.37mmol/L 和 2.38mmol/L)的检测结果不同,专用注射器的游离钙浓度也不同(1.21mmol/L)与第一份血样相比。基于此案例,我们不鼓励实验室经理培训采血员在所有真空采血管后将专用注射器插入针架系统。为避免双重静脉穿刺,应在 EDTA 真空采血管之前,立即在血清管后插入专用注射器进行游离钙测定。