Validation of a Neurofilament Light Chain Assay on a Clinical Autoanalyzer
Bradley B. Collier1, Ahmed Chenna2, Whitney C. Brandon1, Matthew R. Chappell1, John Winslow2, Christos J. Petropoulos2, Andre Valcour2, Joseph Volpe1, Russell P. Grant1
1Center for Esoteric Testing, Labcorp, Burlington, NC, USA, 2Monogram Biosciences, Labcorp, South San Francisco, CA, USA
Objective:

To validate a neurofilament light chain (NfL) assay on a clinical autoanalyzer to enable clinical utility for a broad range of neurogenerative diseases and conditions.

Background:

NfL has been demonstrated to become elevated in serum as a result of several neurodegenerative diseases including MS, Alzheimer’s disease, ALS, Parkinson’s disease, and Huntington disease.  Measurements of NfL could assist with monitoring disease treatment as well as recovery from traumatic brain injuries such as concussions.

This work details the exhaustive LDT assay validation performed at Labcorp for the measurement of NfL in serum and plasma using the Roche cobas® autoanalyzer platform. This assay does not currently have regulatory approval. 

Design/Methods:

Assay validation studies investigating instrument carryover, blood matrix interferences, alternate specimen types, matrix mixing, lower limit of quantitation, analytical measurement range, and accuracy.  Comparison to the predicate assay from Quanterix which has primarily been utilized to establish the clinical utility of NfL levels.  Additionally, robust reference interval studies were performed to establish and verify normal levels of NfL across several patient age groups.

Studies were also performed to determine stability of NfL for a range of specimen types, storage conditions, and operational settings.  The stability of assay materials (reagent, calibrators, and controls) was also demonstrated over time periods that would facilitate operational utility. 

Results:
Acceptable assay and sample performance including correlation to a predicate assays was demonstrated preserving the clinical utility of NfL measurements with this assay.
Conclusions:
The NfL assay is currently available for measurement of patient samples at a Labcorp laboratory.
10.1212/WNL.0000000000202161