Moreau Caroline, Autier Brice, Cavey Thibault, Rouger Emmanuel, Norwood James, Bendavid Claude, Escoffre Martine, Sébillot Martine, Decaux Olivier
Laboratory of Biochemistry and Toxicology, University Hospital Center, Rennes, France; INSERM U-991, University of Rennes 1, Rennes, France.
Laboratory of Biochemistry and Toxicology, University Hospital Center, Rennes, France.
Clin Lymphoma Myeloma Leuk. 2016 Dec;16(12):693-704. doi: 10.1016/j.clml.2016.08.012. Epub 2016 Aug 10.
Free light chain (FLC) assays are essential for diagnosis and follow-up of plasma cell dyscrasia. Two assays are available: Freelite (Binding Site) and N Latex FLC (Siemens). The aim of our study was to evaluate the impact of renal failure on concordance and correlation between the 2 FLC assays.
FLC measurements using both assays were performed on 1215 fresh serum samples from patients with or without monoclonal gammopathy and renal failure. Concordance and correlation were evaluated using Passing-Bablock regression, Pearson correlation coefficient, and the Cohen kappa coefficient, taking into account the renal failure stage (evaluated with Chronic Kidney Disease-Epidemiology Collaboration formulae) and evaluation of treatment response in patients' follow-up.
A good correlation was demonstrated between both assays, irrespective of the renal failure stage (Pearson correlation coefficient > 0.90). For FLC ratio interpretation, there remained 7.6% to 20.8% discordances between the 2 methods throughout the whole range of renal impairment. To evaluate FLC evolution in patient follow-up, 41 patients were selected with at least 6 consecutive serum samples being collected during the study period: we observed a concordant evolution of FLC concentrations between both assays. However, few discrepancies were observed with 4 patients.
Despite adjusted reference ranges for Freelite FLC ratio, there are approximately 12.5% discrepancies in interpretation of FLC ratio between the 2 available assays. They are not linked to renal failure stage and neither of the assays performed better than the other: results must be interpreted taking into account clinical data and the same assay must be used for patient follow-up.
游离轻链（FLC）检测对于浆细胞异常增殖性疾病的诊断和随访至关重要。有两种检测方法可供使用：Freelite（Binding Site公司）和N Latex FLC（西门子公司）。我们研究的目的是评估肾衰竭对这两种FLC检测方法之间一致性和相关性的影响。
使用这两种检测方法对1215份来自患有或未患有单克隆丙种球蛋白病及肾衰竭患者的新鲜血清样本进行FLC测量。使用Passing-Bablock回归、Pearson相关系数和Cohen卡方系数评估一致性和相关性，同时考虑肾衰竭阶段（用慢性肾脏病流行病学协作公式评估）以及患者随访中的治疗反应评估。
两种检测方法之间显示出良好的相关性，与肾衰竭阶段无关（Pearson相关系数>0.90）。对于FLC比值的解读，在整个肾功能损害范围内，两种方法之间仍存在7.6%至20.8%的不一致性。为了评估患者随访中FLC的变化，选择了41例患者，在研究期间至少连续采集6份血清样本：我们观察到两种检测方法之间FLC浓度的变化是一致的。然而，有4例患者存在一些差异。
尽管对Freelite FLC比值进行了参考范围调整，但两种可用检测方法在FLC比值解读上仍存在约12.5%的差异。它们与肾衰竭阶段无关，且两种检测方法表现相当：结果必须结合临床数据进行解读，并且患者随访必须使用同一种检测方法。
