Reference interval and preanalytical properties of serum neurofilament light chain in Scandinavian adults.
Author(s): Hviid CVB, Knudsen CS, Parkner T
Publication: Scand J Clin Lab Invest, 2020, Vol. 80, Page 291-295
PubMed ID: 32077769 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to investigate the effects of patient age and sex, room temperature storage, and freeze/thaw cycling on serum levels of neurofilament light chain (NfL). Serum NfL levels were also compared to those in EDTA plasma and cerebrospinal fluid (CSF) in a small subset of patients.
Conclusion of Paper
Serum NfL levels were correlated with patient age but not sex. Serum NfL levels declined slightly with room temperature storage or freeze/thaw cycles. NfL levels were higher in serum than plasma and were strongly correlated between serum and CSF.
Studies
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Study Purpose
The purpose of this study was to investigate the effects of patient age and sex, room temperature storage, and freeze/thaw cycling on serum levels of NfL. Serum NfL levels were also compared to those in EDTA plasma and CSF in a small subset of patients. Blood was obtained from healthy donors aged 18-67 years and outpatient clinic patients aged 54-87 (diagnosis not specified) into EDTA (52 specimens) or serum (342 specimens) tubes. After 30 min to 4 h of clot time, serum was obtained by centrifugation at 3000 x g for 5 min and stored at -80°C. The effects of patient age were investigated using the serum of 342 blood donors and outpatients (117 males and 117 females) aged 18-67 years. Stability of NfL was investigated by aliquoting twelve serum specimens and storing for 0, 3, or 7 days at room temperature before freezing at -20°C or subjecting to 1, 2, or 3 freeze/thaw cycles between -20°C and room temperature (durations not specified). Comparisons between plasma and serum were investigated using paired specimens from 52 patients. The correlations in NfL between CSF and serum were investigated using leftover specimens from 35 patients who underwent Borrelia burgdorferi antibody screening. NfL levels were assayed using a digital immunoassay on an ultrasensitive Simoa HD-1 platform.
Summary of Findings:
Serum NfL levels were correlated with patient age (R=0.68, P<0.0001) but not sex. The correlation with patient age increased when the NfL levels underwent logarithmic transformation (R=0.826, P<0.0001). Serum NfL levels declined slightly with room temperature storage with 95% remaining after 3 days and 93% after 7 days. Similarly, 92% of the serum NfL remained after three freeze/thaw cycles. NfL levels were higher in serum than plasma (P<0.0001) but strongly correlated between serum and CSF (Spearman’s ρ=0.772, P<0.0001).
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Not specified
- Normal
Platform:
Analyte Technology Platform Protein Immunoassay Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Preaquisition Patient age 18-87 years
Preaquisition Patient gender Female
Male
Biospecimen Aliquots and Components Blood and blood products Plasma
Serum
Biospecimen Acquisition Biospecimen location Plasma
Serum
CSF
Storage Time at room temperature 0 days
3 days
7 days
Storage Freeze/thaw cycling 1 cycle
2 cycles
3 cycles