Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea.
Clin Chem Lab Med. 2023 Apr 6;61(7):1288-1299. doi: 10.1515/cclm-2023-0050. Print 2023 Jun 27.
Free light chain (FLC) is used for the diagnosis and prediction with regard to the progression risk of plasma cell disorders and Freelite reagent using the SPAplus analyzer (The Binding Site) has been one of the widely used option. However, N Latex FLC reagent with the Atellica CH 930 analyzer (Siemens Healthineers) has shown the advantages of automation and high throughput. We aimed to evaluated clinical implication by differential analytical performances of two assays.
A total of 322 serum samples were collected from 193 patients requested for FLC analysis including 131 multiple myeloma patients. The precision, linearity, dilution recovery of N Latex FLC assay was evaluated. We compared the two assays and analyzed the monomer-dimer pattern for discrepant results.
The precision, linearity, and dilution recovery performance was appropriate for the routine use in clinical laboratories. Despite the good correlation within normal range, proportional bias up-to 170% was observed in samples with high concentrations especially for lambda. The higher value samples with N Latex FLC assay contained more monomer forms than controls. All opposite changes of FLC burden by the N Latex FLC assay proved to present concordant dynamic changes when assessed by serum protein electrophoresis.
Clinical laboratories should be aware of the inter-assay variability of FLC quantitative measurements using different platforms, especially for high concentrations of both kappa and lambda measurements, possibly due to monomer/dimer ratio diversity. Clinical interpretations for multiple myeloma disease status might not be dramatically affected only when the same assay is utilized during follow-up periods.
游离轻链（FLC）用于诊断和预测浆细胞疾病的进展风险，使用 SPAplus 分析仪（The Binding Site）的 Freelite 试剂一直是广泛使用的选择之一。然而，Atellica CH 930 分析仪（Siemens Healthineers）上的 N Latex FLC 试剂具有自动化和高通量的优势。我们旨在通过两种检测方法的差异分析性能来评估其临床意义。
共收集了 322 份血清样本，来自 193 名请求进行 FLC 分析的患者，包括 131 名多发性骨髓瘤患者。评估了 N Latex FLC 检测的精密度、线性、稀释回收。我们比较了两种检测方法，并分析了差异结果的单体-二聚体模式。
精密度、线性和稀释回收性能适合于临床实验室的常规使用。尽管在正常范围内相关性良好，但在高浓度样本中观察到比例偏差高达 170%，尤其是 lambda。N Latex FLC 检测法中较高值的样本比对照含有更多的单体形式。当通过血清蛋白电泳评估时，N Latex FLC 检测法所检测的 FLC 负荷的所有相反变化都证明存在一致的动态变化。
临床实验室应该意识到使用不同平台进行 FLC 定量测量的检测间变异性，尤其是对于kappa 和 lambda 测量的高浓度样本，可能是由于单体/二聚体比例多样性所致。仅当在随访期间使用相同的检测方法时，多发性骨髓瘤疾病状态的临床解释可能不会受到显著影响。
