Dashevsky Meir, Bernstein Steven L, Barsky Carol L, Taylor Richard A
Yale School of Medicine, Yale-New Haven Hospital, Department of Emergency Medicine, New Haven, Connecticut.
West J Emerg Med. 2017 Apr;18(3):403-409. doi: 10.5811/westjem.2017.1.30532. Epub 2017 Mar 13.
Point-of-care (POC) testing allows for more time-sensitive diagnosis and treatment in the emergency department (ED) than sending blood samples to the hospital central laboratory (CL). However, many ED patients have blood sent to both, either out of clinical custom, or because clinicians do not trust the POC values. The objective of this study was to examine the level of agreement between POC and CL values in a large cohort of ED patients.
In an urban, Level I ED that sees approximately 120,000 patients/year, all patients seen between March 1, 2013, and October 1, 2014, who had blood sent to POC and CL labs had levels of agreement measured between serum sodium, potassium, blood urea nitrogen (BUN), creatinine, and hematocrit. We extracted data from the hospital's clinical information system, and analyzed agreement with the use of Bland-Altman plots, defining both 95% confidence intervals (CIs) and more conservative CIs based on clinical judgment.
Out of 163,661 patients seen during the study period, 14,567 had blood samples sent both for POC and CL analysis. Using clinical criteria, the levels of agreement for sodium were 98.6% (within 5mg/dL), for potassium 90.7% (0.5 mmol/L), for BUN 89.0% (within 5 mg/dL), for creatinine 94.5% (within 0.3 mg/dL), for hematocrit 96.5% (within 5 g/dL).
Agreement between POC and CL values is excellent. Restricting the analysis to clinically important levels of agreement continues to show a high level of agreement. The data suggest that sending a serum sample to the hospital CL for duplicate assays is unnecessary. This may result in substantial savings and shorter ED lengths of stay.
即时检验（POC）相较于将血样送至医院中心实验室（CL），能在急诊科（ED）实现更具时效性的诊断和治疗。然而，许多急诊科患者的血样会同时送往这两个地方，这要么是出于临床习惯，要么是因为临床医生不信任即时检验的结果。本研究的目的是在一大群急诊科患者中，检验即时检验结果与中心实验室结果之间的一致性水平。
在一家每年接待约120,000名患者的城市一级急诊科，对2013年3月1日至2014年10月1日期间所有血样同时送往即时检验实验室和中心实验室的患者，测定血清钠、钾、血尿素氮（BUN）、肌酐和血细胞比容的一致性水平。我们从医院的临床信息系统中提取数据，并使用Bland-Altman图分析一致性，同时基于临床判断定义95%置信区间（CI）和更保守的置信区间。
在研究期间就诊的163,661名患者中，有14,567人的血样同时进行了即时检验和中心实验室分析。根据临床标准，钠的一致性水平为98.6%（在5mg/dL范围内），钾为90.7%（0.5 mmol/L），血尿素氮为89.0%（在5 mg/dL范围内），肌酐为94.5%（在0.3 mg/dL范围内），血细胞比容为96.5%（在5 g/dL范围内）。
即时检验结果与中心实验室结果之间的一致性非常好。将分析限制在具有临床重要性的一致性水平上，仍显示出高度一致性。数据表明，将血清样本送往医院中心实验室进行重复检测是不必要的。这可能会带来大幅节省，并缩短急诊科的住院时间。
