Medical School, University of Sheffield, Sheffield S10 2JA, UK.
Ann Clin Biochem. 2011 Nov;48(Pt 6):562-5. doi: 10.1258/acb.2011.011099. Epub 2011 Sep 23.
Phlebotomy is a potential cause of preanalytical errors. We have observed phlebotomy in routine practice in a busy Emergency Department, to see how current practice compares with optimal blood sampling.
Phlebotomy episodes were audited and compared with standard procedures. A computer-based search of the number of haemolysed samples from Emergency Medicine and hospital inpatients was reviewed.
Four different ways of taking blood were observed: cannulation and a syringe (38%), cannula with evacuated tube and adaptor (42%), syringe and needle into vein (14%) and evacuated tube system used conventionally (6%). Where a syringe was used, two methods of transfer into the sample tube were observed; needle kept on with cap piercing (77%) and needle and evacuated cap both removed (23%). On 20 out of 50 phlebotomy episodes (40%), the potassium-EDTA tube was filled prior to the biochemistry serum gel tube. A search of the laboratory computer records for ward-based phlebotomy found 30 of 1034 samples were haemolysed (2.9%). In the 50 phlebotomy episodes in the Majors area of the Emergency Department, 24% produced a haemolysed sample (P < 0.0001). For samples taken from all areas of Emergency Medicine over a seven-day period, 52 of 485 were haemolysed (10.7%; P < 0.0001).
This study has shown that phlebotomy techniques in the Emergency Department deviate from standard practice significantly. This may well be a reason for the much higher frequency of haemolysed samples and with the wrong order of collection the possibility of potassium-EDTA-contaminated samples.
采血是分析前误差的一个潜在原因。我们观察了繁忙的急诊科中的常规采血操作，以了解当前实践与最佳采血方法的差异。
对采血操作进行审核，并与标准程序进行比较。还对来自急诊医学和住院患者的溶血样本数量进行了计算机检索。
观察到 4 种不同的采血方式：套管针和注射器（38%）、带真空管和适配器的套管（42%）、注射器和静脉内的针头（14%）以及常规使用的真空管系统（6%）。在使用注射器的情况下，观察到两种将血液转移到样品管中的方法：带帽刺穿的针头（77%）和针头和真空管帽都移除（23%）。在 50 次采血操作中的 20 次（40%）中，钾-EDTA 管在生化血清凝胶管之前被填满。对实验室计算机记录中基于病房的采血进行检索，发现 1034 个样本中有 30 个（2.9%）溶血。在急诊科的主要区域进行的 50 次采血操作中，24%产生了溶血样本（P<0.0001）。在为期 7 天的急诊医学所有区域采集的样本中，有 52 个（10.7%；P<0.0001）溶血。
本研究表明，急诊科的采血技术与标准实践有很大的差异。这很可能是溶血样本频率更高的原因，而且采集顺序错误，也有可能导致钾-EDTA 污染的样本。
