Nguyen-Khoa Thao, Borgard Jean-Pierre, Miled Ryad, Rota Michèle
Service de biochimie, Hôpital universitaire Necker-Enfants Malades AP-HP, Paris, France.
Ann Biol Clin (Paris). 2013 Jul-Aug;71(4):443-8. doi: 10.1684/abc.2013.0866.
Sweat chloride (Cl(-)) measurement is a key step for the diagnosis of cystic fibrosis. The coulometric technique is validated in this context by international guidelines. The aim of our study was to evaluate the assay for sweat Cl(-) ions using direct potentiometry on disposable cassette (Spotchem™ SE EL-1520, Elitech-Arkray) by comparing results to those obtained on the same sample, by coulometry (Chloride analyser Sherwood 926S, Dutscher). To complete our table of correspondence between the results of Cl(-) ions and sweat conductivity (Sweat Check™ 3100), conductivity has been also achieved for 99 of the 139 sweat samples studied. Linearity of each technique performed extends from 10 to 120 mmol/L. The coefficients of variation within and between runs are < 5%. Comparison of 139 results (Passing - Bablock regression) shows a significant difference (p < 0.001): [Spotchem] = 1.026 [Chloride analyser] + 1.8, r = 0.996. After correction with regression factors, only 6 pairs of values (4.6%) had a difference greater than ± 5 mmol/L). The results of conductivity measurement is strongly correlated with those of Cl(-) ions (r = 0.959 for Chloride analyser and 0.965 for Spotchem; p = 0.576) with a linear relationship between the decision thresholds from 30 to 60 mmol/L Cl(-). Sweat Cl(-) determinations using Spotchem™ analyser meet the criteria required by analytical recommendations. The technique is standardized, easy to perform and fast. Its good practicability makes the sweat test independent to operator and allows point-of care use.
汗液氯化物（Cl⁻）测量是诊断囊性纤维化的关键步骤。在这方面，库仑法技术已得到国际指南的验证。我们研究的目的是通过将使用一次性检测盒（Spotchem™ SE EL - 1520，爱帝康 - 阿克莱）直接电位法检测汗液Cl⁻离子的结果与使用库仑法（氯化物分析仪Sherwood 926S，杜舍尔）对同一样本获得的结果进行比较，来评估该检测方法。为了完善我们的Cl⁻离子结果与汗液电导率（Sweat Check™ 3100）之间的对应表，在所研究的139份汗液样本中的99份样本也进行了电导率检测。每种技术的线性范围为10至120 mmol/L。批内和批间变异系数均<5%。对139个结果进行比较（帕氏 - 巴布洛克回归）显示存在显著差异（p < 0.001）：[Spotchem] = 1.026[氯化物分析仪] + 1.8，r = 0.996。在用回归因子校正后，只有6对数值（4.6%）的差异大于±5 mmol/L。电导率测量结果与Cl⁻离子结果高度相关（氯化物分析仪的r = 0.959，Spotchem的r = 0.965；p = 0.576），在30至60 mmol/L Cl⁻的判定阈值之间呈线性关系。使用Spotchem™分析仪测定汗液Cl⁻符合分析建议要求的标准。该技术标准化、易于操作且快速。其良好的实用性使汗液检测独立于操作人员，并允许在床旁使用。
