Department of Neurology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.
Sci Rep. 2021 May 26;11(1):11034. doi: 10.1038/s41598-021-90639-z.
Neurofilament light chain (NfL) has emerged as a biomarker of neuroaxonal damage in several neurologic conditions. With increasing availability of fourth-generation immunoassays detecting NfL in blood, aspects of pre-analytical stability of this biomarker remain unanswered. This study investigated NfL concentrations in serum and plasma samples of 32 patients with neurological diagnoses using state of the art Simoa technology. We tested the effect of delayed freezing of up to 7 days and statistically determined stability and validity of measured concentrations. We found concentrations of NfL in serum and plasma to remain stable at room temperature when processing of samples is delayed up to 7 days (serum: mean absolute difference 0.9 pg/mL, intraindividual variation 1.2%; plasma: mean absolute difference 0.5 pg/mL, intraindividual variation 1.3%). Consistency of these results was nearly perfect for serum and excellent for plasma (intraclass correlation coefficients 0.99 and 0.94, respectively). In conclusion, the soluble serum and plasma NfL concentration remains stable when unprocessed blood samples are stored up to 7 days at room temperature. This information is essential for ensuring reliable study protocols, for example, when shipment of fresh samples is needed.
神经丝轻链 (NfL) 已成为几种神经疾病中神经轴突损伤的生物标志物。随着第四代免疫分析法在血液中检测 NfL 的可用性不断增加，该生物标志物的一些分析前稳定性问题仍未得到解答。本研究使用最先进的 Simoa 技术，检测了 32 名神经诊断患者的血清和血浆样本中的 NfL 浓度。我们测试了延迟冷冻长达 7 天的影响，并从统计学上确定了测量浓度的稳定性和有效性。我们发现，当延迟处理样本长达 7 天时，血清和血浆中的 NfL 浓度在室温下保持稳定（血清：平均绝对差异 0.9pg/mL，个体内变异 1.2%；血浆：平均绝对差异 0.5pg/mL，个体内变异 1.3%）。对于血清，这些结果的一致性几乎是完美的，对于血浆，结果也非常好（血清和血浆的组内相关系数分别为 0.99 和 0.94）。总之，未处理的血液样本在室温下储存长达 7 天时，血清和血浆中可溶性 NfL 浓度保持稳定。这一信息对于确保可靠的研究方案至关重要，例如，当需要运送新鲜样本时。
