Ceriotti Ferruccio, Marino Irene, Motta Andrea, Carobene Anna
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Clin Chem Lab Med. 2017 Nov 27;56(1):162-169. doi: 10.1515/cclm-2017-0159.
Procalcitonin (PCT) is a recognized marker of sepsis, and its use is expanding to antibiotic stewardship. The aim of this study was the evaluation of two methods: Diazyme PCT on Roche Cobas c702 (PCT-D) and BRAHMS PCT on Roche Cobas e602 analyzers (PCT-BR) in comparison with BRAHMS PCT-sensitive Kryptor (PCT-BK).
Imprecision was assessed at six critical concentrations following the CLSI EP5-A3; limits of detection (LoDs) were checked according to CLSI EP17-A2; linearity was tested, and method comparison was performed on 239 serum samples.
Overall CVs ranged from 12.58% to 5.97% for PCT-D, from 3.94% to 1.70% for PCT-BR and from 6.57% to 1.90% for PCT-BK. LoDs were 0.143 μg/L, 0.014 μg/L, 0.040 μg/L for PCT-D, PCT-BR and PCT-BK, respectively. The functional assay sensitivity was 0.24 μg/L for PCT-D, 0.045 μg/L for PCT-BK and <0.035 μg/L for PCT-BR. PCT-BR was linear up to 68.7 μg/L, PCT-BK up to 43 μg/L and PCT-D up to 27.2 μg/L. Method comparison: PCT-D=0.6543 PCT-BK+0.014, r=0.8463 (but 0.44 if calculated on 0-5 μg/L range); PCT-BR=0.9125 PCT-BK+0.021, r=0.9917. Cohen's κ ranged from 45.2% at 0.25 μg/L to 57.0% at 2.00 μg/L between PCT-D and PCT-BK, whereas it ranged from 89% to 81.3% between PCT-BR and PCT-BK.
The PCT-D performances were significantly different from those of PCT-BR and PCT-BK regarding sensitivity, precision, linearity and agreement at clinical cutoffs. For some patients with serial testing, significantly deviating results were obtained compared to reference. In contrast to Roche PCT assay, it does not seem feasible to use BRAHMS PCT cutoffs for the Diazyme test.
降钙素原（PCT）是脓毒症公认的标志物，其应用正扩展至抗生素管理领域。本研究的目的是评估两种方法：罗氏Cobas c702分析仪上的Diazyme PCT（PCT-D）和罗氏Cobas e602分析仪上的BRAHMS PCT（PCT-BR），并与BRAHMS PCT敏感型Kryptor（PCT-BK）进行比较。
按照CLSI EP5-A3在六个关键浓度下评估不精密度；根据CLSI EP17-A2检查检测限（LoD）；测试线性，并对239份血清样本进行方法比较。
PCT-D的总体变异系数（CV）范围为12.58%至5.97%，PCT-BR为3.94%至1.70%，PCT-BK为6.57%至1.90%。PCT-D、PCT-BR和PCT-BK的LoD分别为0.143μg/L、0.014μg/L、0.040μg/L。PCT-D的功能测定灵敏度为0.24μg/L，PCT-BK为0.045μg/L，PCT-BR＜0.035μg/L。PCT-BR在高达68.7μg/L时呈线性，PCT-BK在高达43μg/L时呈线性，PCT-D在高达27.2μg/L时呈线性。方法比较：PCT-D = 0.6543PCT-BK + 0.014，r = 0.8463（但在0 - 5μg/L范围内计算时为0.44）；PCT-BR = 0.9125PCT-BK + 0.021，r = 0.9917。PCT-D与PCT-BK之间的Cohen's κ在0.25μg/L时为45.2%，在2.00μg/L时为57.0%，而PCT-BR与PCT-BK之间的Cohen's κ在89%至81.3%之间。
在灵敏度、精密度、线性以及临床临界值的一致性方面，PCT-D的性能与PCT-BR和PCT-BK存在显著差异。对于一些进行连续检测的患者，与参考值相比获得了明显偏差的结果。与罗氏PCT检测不同，将BRAHMS PCT临界值用于Diazyme检测似乎不可行。
