scholarly journals Seven day pre-analytical stability of serum and plasma neurofilament light chain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Patrick Altmann ◽  
Markus Ponleitner ◽  
Paulus Stefan Rommer ◽  
Helmuth Haslacher ◽  
Patrick Mucher ◽  
...  
Keyword(s):  
Light Chain ◽  
Room Temperature ◽  
Intraclass Correlation ◽  
Absolute Difference ◽  
Intraindividual Variation ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Mean Absolute Difference ◽  
Analytical Stability ◽  
Study Protocols

AbstractNeurofilament 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.

scholarly journals Serum neurofilament light chain withstands delayed freezing and repeated thawing

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Patrick Altmann ◽  
Fritz Leutmezer ◽  
Heidemarie Zach ◽  
Raphael Wurm ◽  
Miranda Stattmann ◽  
...  
Keyword(s):  
Light Chain ◽  
Absolute Difference ◽  
Intraindividual Variation ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Mean Absolute Difference ◽  
Analytical Stability ◽  
Neurologic Disorders ◽  
Biomarker Research ◽  
High Throughput Assay

AbstractSerum neurofilament light chain (sNfL) and its ability to expose axonal damage in neurologic disorders have solicited a considerable amount of attention in blood biomarker research. Hence, with the proliferation of high-throughput assay technology, there is an imminent need to study the pre-analytical stability of this biomarker. We recruited 20 patients with common neurological diagnoses and 10 controls (i.e. patients without structural neurological disease). We investigated whether a variation in pre-analytical variables (delayed freezing up to 24 h and repeated thawing/freezing for up to three cycles) affects the measured sNfL concentrations using state of the art Simoa technology. Advanced statistical methods were applied to expose any relevant changes in sNfL concentration due to different storing and processing conditions. We found that sNfL concentrations remained stable when samples were frozen within 24 h (mean absolute difference 0.2 pg/ml; intraindividual variation below 0.1%). Repeated thawing and re-freezing up to three times did not change measured sNfL concentration significantly, either (mean absolute difference 0.7 pg/ml; intraindividual variation below 0.2%). We conclude that the soluble sNfL concentration is unaffected at 4–8 °C when samples are frozen within 24 h and single aliquots can be used up to three times. These observations should be considered for planning future studies.

scholarly journals Assessing Plasma Levels of α-Synuclein and Neurofilament Light Chain by Different Blood Preparation Methods

2021 ◽  
Vol 13 ◽  
Author(s):  
Kuo-Hsuan Chang ◽  
Kou-Chen Liu ◽  
Chao-Sung Lai ◽  
Shieh-Yueh Yang ◽  
Chiung-Mei Chen
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Light Chain ◽  
Plasma Levels ◽  
Room Temperature ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Preparation Methods ◽  
Different Types ◽  
Temperature Preparation

The potential biomarkers of Parkinson’s disease are α-synuclein and neurofilament light chain (NFL). However, inconsistent preanalytical preparation of plasma could lead to variations in levels of these biomarkers. Different types of potassium salts of EDTA and different centrifugation temperatures during plasma preparation may affect the results of α-synuclein and NFL measurements. In this study, we prepared plasma from eight patients with Parkinson’s disease (PD) and seven healthy controls (HCs) by using di- and tri-potassium (K2- and K3-) EDTA tubes and recruited a separated cohort with 42 PD patients and 40 HCs for plasma samples prepared from whole blood by centrifugation at room temperature and 4°C, respectively, in K2-EDTA tubes. The plasma levels of α-synuclein and NFL in K2- and K3-EDTA were similar. However, the levels of α-synuclein in the plasma prepared at 4°C (101.57 ± 43.43 fg/ml) were significantly lower compared with those at room temperature (181.23 ± 196.31 fg/ml, P < 0.001). Room temperature preparation demonstrated elevated plasma levels of α-synuclein in PD patients (256.6 ± 50.2 fg/ml) compared with the HCs (102.1 ± 0.66 fg/ml, P < 0.001), whereas this increase in PD was not present by preparation at 4°C. Both plasma preparations at room temperature and 4°C demonstrated consistent results of NFL, which are increased in PD patients compared with HCs. Our findings confirmed that K2- and K3-EDTA tubes were interchangeable for analyzing plasma levels of α-synuclein and NFL. Centrifugation at 4°C during plasma preparation generates considerable reduction and variation of α-synuclein level that might hinder the detection of α-synuclein level changes in PD.

Increased frequency of proinflammatory CD4 T cells and pathological levels of serum neurofilament light chain in adult drug‐resistant epilepsy

Epilepsia ◽  
2020 ◽  
Author(s):  
Oumarou Ouédraogo ◽  
Rose‐Marie Rébillard ◽  
Hélène Jamann ◽  
Victoria Hannah Mamane ◽  
Marie‐Laure Clénet ◽  
...  
Keyword(s):  
T Cells ◽  
Light Chain ◽  
Cd4 T Cells ◽  
Drug Resistant ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Drug Resistant Epilepsy

scholarly journals Plasma NfL levels and longitudinal change rates in C9orf72 and GRN-associated diseases: from tailored references to clinical applications

2021 ◽  
pp. jnnp-2021-326914
Author(s):  
Dario Saracino ◽  
Karim Dorgham ◽  
Agnès Camuzat ◽  
Daisy Rinaldi ◽  
Armelle Rametti-Lacroux ◽  
...  
Keyword(s):  
Single Molecule ◽  
Light Chain ◽  
Rate Of Change ◽  
Longitudinal Change ◽  
Youden Index ◽  
Clinical Genetic ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Link Type ◽  
Therapeutic Trials

ObjectiveNeurofilament light chain (NfL) is a promising biomarker in genetic frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). We evaluated plasma neurofilament light chain (pNfL) levels in controls, and their longitudinal trajectories in C9orf72 and GRN cohorts from presymptomatic to clinical stages.MethodsWe analysed pNfL using Single Molecule Array (SiMoA) in 668 samples (352 baseline and 316 follow-up) of C9orf72 and GRN patients, presymptomatic carriers (PS) and controls aged between 21 and 83. They were longitudinally evaluated over a period of >2 years, during which four PS became prodromal/symptomatic. Associations between pNfL and clinical–genetic variables, and longitudinal NfL changes, were investigated using generalised and linear mixed-effects models. Optimal cut-offs were determined using the Youden Index.ResultspNfL levels increased with age in controls, from ~5 to~18 pg/mL (p<0.0001), progressing over time (mean annualised rate of change (ARC): +3.9%/year, p<0.0001). Patients displayed higher levels and greater longitudinal progression (ARC: +26.7%, p<0.0001), with gene-specific trajectories. GRN patients had higher levels than C9orf72 (86.21 vs 39.49 pg/mL, p=0.014), and greater progression rates (ARC:+29.3% vs +24.7%; p=0.016). In C9orf72 patients, levels were associated with the phenotype (ALS: 71.76 pg/mL, FTD: 37.16, psychiatric: 15.3; p=0.003) and remarkably lower in slowly progressive patients (24.11, ARC: +2.5%; p=0.05). Mean ARC was +3.2% in PS and +7.3% in prodromal carriers. We proposed gene-specific cut-offs differentiating patients from controls by decades.ConclusionsThis study highlights the importance of gene-specific and age-specific references for clinical and therapeutic trials in genetic FTD/ALS. It supports the usefulness of repeating pNfL measurements and considering ARC as a prognostic marker of disease progression.Trial registration numbersNCT02590276 and NCT04014673.

Serum neurofilament light chain levels reflect cortical neurodegeneration in de novo Parkinson's disease

2020 ◽  
Vol 74 ◽  
pp. 43-49 ◽  
Author(s):  
Frederic Sampedro ◽  
Rocío Pérez-González ◽  
Saul Martínez-Horta ◽  
Juan Marín-Lahoz ◽  
Javier Pagonabarraga ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Light Chain ◽  
De Novo ◽  
Neurofilament Light Chain ◽  
Neurofilament Light
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