Neurofilament light chain (NF-L) is a neuronal cytoskeletal protein released into biofluids upon axonal injury and neurodegeneration. Elevated plasma and cerebrospinal fluid NF-L levels have been reported across a broad range of neurological conditions, including amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer's disease, and traumatic brain injury. Elevated plasma NF-L is a sensitive, quantitative indicator of ongoing neurodegeneration — rising before symptom onset, tracking disease progression, and responding to effective treatment. This translates into a powerful, non-invasive tool that can:

▸ Enrich and stratify trial populations by neurological damage burden at screening

▸ Serve as a pharmacodynamic endpoint to demonstrate target engagement

▸ Provide objective evidence of disease modification or slowing of neurodegeneration

▸ Support regulatory submissions as an exploratory, secondary, or co-primary endpoint

Established across the major neurodegenerative indications

Alzheimer's disease · MSA · ALS · Multiple sclerosis · Huntington's disease · Traumatic brain injury

NF-L has been accepted by the FDA and EMA as an exploratory biomarker in multiple IND and regulatory packages, and is increasingly featured as a secondary endpoint in Phase II/III neurology trials. By choosing a CLIA-certified, Good Clinical Laboratory Practice (GCLP)-compliant NF-L service, sponsors gain a defensible, audit-ready data package with the analytical rigor required for regulatory scrutiny.

The SBH Sciences NF-L Analytical Validation Program

All analytical validation described in this report — including every ELLA™ Simple Plex run, precision study, interference testing, stability testing, and carryover assessment — was performed by SBH Sciences in its CLIA-certified laboratory operating under GCLP guidelines, in collaboration with Neurodex.

This validation establishes SBH Sciences as a fully qualified provider of high-integrity NF-L biomarker data for clinical trial applications, using the ELLA™ Simple Plex immunoassay platform (Bio-Techne).

SBH Sciences provides sponsors with:

Regulatory readiness

✓ CLIA-certified laboratory operations
✓ GCLP-compliant SOPs, documentation, and QA oversight
✓ Full audit trail and chain of custody
✓ Complete method validation package generated from SBH-run studies
✓ Suitable for FDA and EMA submissions

Turnaround and logistics

✓ EDTA plasma compatibility
✓ LIMS-based sample tracking and storage
✓ Batch reporting with QC flagging
✓ Secure electronic data transfer (SFTP / EDC integration)

Validation at a Glance

The SBH Sciences validation program demonstrates that the ELLA NF-L assay meets all analytical performance criteria required for clinical biomarker deployment. All results below are derived from seven independent SBH Sciences analytical runs.

1. Assay Platform and Validation Design

1.1 ELLA™ Simple Plex technology

The ELLA™ Simple Plex platform (Bio-Techne) uses single-use microfluidic cartridges containing antibody-coated nanoreactors. This closed-system architecture eliminates cross-contamination, minimizes operator variability, and enables high-sensitivity chemiluminescent detection.

For NF-L, the assay spans approximately 2–2,000 pg/mL, covering both healthy baseline levels (~5–20 pg/mL) and advanced neurodegenerative disease ranges (>1,000 pg/mL).

1.2 SBH Sciences validation design

All validation studies were executed by SBH Sciences across seven independent analytical runs in single-plate format.

Three human EDTA plasma donors with endogenous NF-L levels (~7–18 pg/mL) were used throughout. Three spike concentrations were applied:

• Low: 6 pg/mL (near LLOQ)
• Mid: 54 pg/mL
• High: 486 pg/mL

These cover >95% of clinically relevant NF-L concentrations.

Run Structure:

• Run 1: Linearity (8-point dilution), selectivity, intra-run precision
• Runs 2–7: Precision across standards and plasma samples
• Runs 2–3: Interference testing (hemolysis, lipids, icterus, biotin)
• Run 4: Stability (4°C storage + freeze-thaw cycling)
• Run 7: Carryover and sensitivity assessment

2. Analytical Performance Results

2.1 Linearity

SBH Sciences demonstrated exceptional linearity across the full analytical range (2–1458 pg/mL), with log-log regression yielding R² ≥ 0.9999.

Recovery remained within 80–120% across mid-to-high concentrations, with expected deviation near the LLOQ reflecting standard immunoassay behavior.

Interpretation: The assay provides reliable proportional quantification across the entire clinically relevant range for neurodegenerative disease trials.

2.2 Specificity

No cross-reactivity was observed with:

• Neurofilament medium (NFM)
• Neurofilament heavy (NFH)
  
• Peripherin

All tested conditions remained below LLOQ, confirming high analytical specificity for NF-L in complex plasma matrices.

2.3 Intra-run precision

Across all SBH Sciences runs (n=21 total measurements per level):

• %CV ≤ 12% at all concentrations
• High concentration precision: ≤ 5.2% CV
• Low concentration (near LLOQ): 4.0–12.0% CV

All results met the ≤15% acceptance criterion.

Interpretation: The assay supports reliable detection of 20–30% longitudinal changes in NF-L in clinical studies.

2.4 Matrix spike recovery

Across three independent plasma donors:

• Recovery range: ~85–115%
• Consistent performance across low, mid, and high spike levels
• No donor-dependent bias observed
  

Interpretation: Robust performance across heterogeneous clinical trial populations.

2.5 Interference testing

SBH Sciences evaluated hemoglobin, lipids, bilirubin, and biotin.

• Hemoglobin: interference only at severe hemolysis levels
• Lipids: no measurable effect
• Bilirubin: negative bias only at clinically severe jaundice levels
• Biotin: no interference observed

Conclusion: Standard GCLP pre-analytical controls are sufficient to mitigate interference risk.

2.6 Sample stability

NF-L demonstrated strong stability under real-world trial conditions:

• 4°C stability: up to 32 hours
• Freeze-thaw stability: up to 3 cycles
• Recovery: 87–119% across all conditions
  

Interpretation: Fully compatible with multi-site sample shipping and centralized biobanking workflows.

2.7 Carryover

Carryover was minimal:

• Observed bias: 5.6%
• Acceptance threshold: <10%

Interpretation: The ELLA cartridge system effectively eliminates carryover risk in routine use.

2.8 Sensitivity

All blank samples were below LLOQ (~2 pg/mL), confirming:

• No background signal
• Full suitability for low-level NF-L detection in healthy controls

3. Clinical Validation in Neurological Disease

All clinical samples were measured using SBH Sciences’ validated ELLA NF-L protocol.

3.1 ALS

• Controls (n=123): median 16.0 pg/mL
• ALS (n=114): median 51.2 pg/mL
• Fold change: 3.2×
• p < 0.0001
  

Interpretation: Strong separation consistent with published ALS NF-L distributions and suitable for stratification and pharmacodynamic monitoring.

3.2 Alzheimer’s disease

• Controls (n=187): median 18.9 pg/mL
• AD (n=67): median 44.9 pg/mL
• Fold change: 2.4×
• p < 0.0001
  

Interpretation: Robust elevation consistent with neuroaxonal injury and suitable as a longitudinal pharmacodynamic biomarker.

3.3 Cross-indication relevance

Across both ALS and AD datasets, SBH Sciences demonstrated:

• Consistent analytical performance across disease contexts
• Full sample coverage within validated assay range
• Strong statistical separation between patients and controls
  

This confirms NF-L’s utility as a broadly deployable neurodegeneration biomarker in clinical trials.

4. Fit for Clinical Trials: Practical Implications

SBH Sciences NF-L Clinical Biomarker Service

The ELLA NF-L assay is fully validated and operational within SBH Sciences as a GCLP-compliant biomarker service and CLIA-certified through our subsidiary SBH Diagnostics.

SBH Sciences provides:

• Full analytical validation package

• Clinical trial sample testing

• Biomarker strategy support

• Data interpretation and regulatory documentation support
  

The service is immediately available for Phase I–III neurodegenerative disease trials.

Ready to add NF-L1 to your biomarker strategy? Contact SBH Sciences to learn more.

mstewart@sbhscience.com | www.sbhsciences.com