Haag M D, Kelly J R, Ho A, Seccombe D W
Department of Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands.
Clin Biochem. 2000 Aug;33(6):449-56. doi: 10.1016/s0009-9120(00)00150-8.
To assess the accuracy of potassium measurements in clinical laboratories across Canada.
The flame atomic emission spectrophotometry reference method for the determination of potassium was established at the Canadian Reference Laboratory by using National Institute of Science and Technology standard reference materials. The method was subsequently used to assign target values for potassium to Canadian Reference Laboratory's External Quality Assessment human-serum-based testing material. A total of 503 laboratories participated and 9,279 individual External Quality Assessment test results were included in the study. Bias was determined by using difference plots.
Clinically significant bias (>1.6%) was observed in 45.9% of the laboratories. Bias ranged from 0.34 mmol/L to -0.54 mmol/L. At low concentrations (<3.5 mmol/L) a positive bias was most frequently observed (14.7% of analytical systems). At high potassium concentrations (>5.1 mmol/L) a negative bias was most frequently observed (31.4% of analytical systems).
Inaccuracy in potassium results can contribute to test redundancy and mismanagement of patients, while prohibiting the merger of laboratory data from disparate testing sites for the purpose of trending and consolidation within a "universal health record." Inaccurate test results and the lack of standardization among laboratories adversely impact our ability to establish common reference intervals and critical limits. This inability has an adverse effect on medical decisions and patient care.
评估加拿大各临床实验室钾测量的准确性。
加拿大参考实验室采用美国国家标准与技术研究院的标准参考物质，建立了火焰原子发射分光光度法测定钾的参考方法。随后，该方法被用于为加拿大参考实验室基于人血清的外部质量评估检测材料指定钾的目标值。共有503家实验室参与，9279份个体外部质量评估测试结果纳入本研究。采用差异图确定偏差。
45.9%的实验室观察到具有临床意义的偏差（>1.6%）。偏差范围为0.34 mmol/L至 -0.54 mmol/L。在低浓度（<3.5 mmol/L）时，最常观察到正偏差（14.7%的分析系统）。在高钾浓度（>5.1 mmol/L）时，最常观察到负偏差（31.4%的分析系统）。
钾检测结果不准确会导致检测冗余和患者管理不善，同时阻碍为建立“通用健康记录”中的趋势和整合而合并来自不同检测地点的实验室数据。检测结果不准确以及实验室之间缺乏标准化，会对我们建立通用参考区间和危急值的能力产生不利影响。这种情况对医疗决策和患者护理有不良影响。
