Murthy J N, Hicks J M, Soldin S J
Department of Laboratory Medicine, Children's National Medical Center, Washington, DC 20010, USA.
Clin Biochem. 1997 Jul;30(5):385-9. doi: 10.1016/s0009-9120(97)00046-5.
To evaluate the Point-of-Care (POC) i-STAT system for measuring blood gases (pH, pCO2, pO2) and whole blood electrolytes (sodium, Na+, potassium, K+ and ionized calcium, iCa2+) in the neonatal and pediatric intensive care units.
The i-STAT system was evaluated for imprecision, necessity of running quality control and accuracy. Comparison of patients' samples analyzed by the i-STAT system and the Ciba Coming 288 blood gas analyzer were performed. The reliability of the i-STAT system when performed by non-laboratory personnel was assessed.
The system was evaluated for imprecision and linearity using three concentrations of aqueous standards. Except for pO2, the %CVs were < 3.0 for all the analytes (pH, pCO2, Na+, K+ and iCa2+) at all the three concentrations. Using whole blood studies the precision data gave %CVs that were < 3.5 for all the analytes. Linearity studies showed good linearity over the five different concentrations tested. Comparison of the i-STAT and the Ciba Coming 288 blood gas analyzer was assessed by split sample measurement. Patients' results from the i-STAT correlated well with the Ciba Coming 288 blood gas analyzer (r = 0.99 for pH, pCO2 and pO2 and 0.95 to 0.99 for Na+ and K+) with the exception of iCa2+ (r = 0.73). There was no significant difference in the results when operated by PICU/NICU nurses or laboratory personnel. A further study was made to assess whether routine quality control (QC) samples are necessary when using the i-STAT system. The regression analysis (slope and correlation coefficient) of the results from instruments run with and without QC samples gave results close to 1, indicating that there is no need to run additional quality control (QC).
The POC testing analyzer i-STAT is a reliable alternative to the traditional blood gas analyzers and provides marginal improvement in turnaround time when compared with the service received from the PICU/NICU laboratory. Costs need to be carefully controlled.
评估即时检验（POC）i-STAT系统在新生儿和儿科重症监护病房测量血气（pH、pCO₂、pO₂）及全血电解质（钠、Na⁺、钾、K⁺和离子钙、iCa²⁺）的性能。
对i-STAT系统的不精密度、运行质量控制的必要性及准确性进行评估。将i-STAT系统分析的患者样本与西巴-科宁288血气分析仪分析的结果进行比较。评估非实验室人员操作i-STAT系统时的可靠性。
使用三种浓度的水溶液标准品评估系统的不精密度和线性。除pO₂外，所有分析物（pH、pCO₂、Na⁺、K⁺和iCa²⁺）在三种浓度下的变异系数百分比（%CV）均<3.0。通过全血研究，所有分析物的精密度数据给出的%CV均<3.5。线性研究表明，在所测试的五种不同浓度范围内具有良好的线性。通过分割样本测量评估i-STAT与西巴-科宁288血气分析仪的比较。i-STAT系统的患者结果与西巴-科宁288血气分析仪相关性良好（pH、pCO₂和pO₂的r = 0.99，Na⁺和K⁺的r = 0.95至0.99），离子钙（iCa²⁺）除外（r = 0.73）。由儿科重症监护病房/新生儿重症监护病房护士或实验室人员操作时，结果无显著差异。进一步研究评估使用i-STAT系统时是否需要常规质量控制（QC）样本。对运行有和没有QC样本的仪器结果进行回归分析（斜率和相关系数），结果接近1，表明无需进行额外的质量控制（QC）。
即时检验分析仪i-STAT是传统血气分析仪的可靠替代品，与儿科重症监护病房/新生儿重症监护病房实验室提供的服务相比，周转时间略有改善。成本需要仔细控制。
