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Official Description

Neurofilament light chain (NfL)

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

Neurofilament light chain (NfL) is a significant biomarker that indicates the level of neuronal axon degeneration occurring in the subcortex of the brain. Elevated levels of NfL can be detected in both plasma and cerebrospinal fluid (CSF) and are associated with various neurodegenerative disorders, including Alzheimer's disease, multiple sclerosis, frontotemporal dementia, and amyotrophic lateral sclerosis. The presence of NfL in the blood is particularly noteworthy, as it is typically not found in significant amounts under normal conditions. This biomarker is released into the CSF during neuronal injury and subsequently enters the bloodstream. The plasma-based assay for NfL is particularly valuable in clinical settings, as it aids in differentiating whether a decline in cognitive function is attributable to a neurodegenerative disorder. Traditional testing methods primarily utilize CSF samples; however, advancements have led to the development of blood tests that can detect NfL levels. These blood-based tests not only streamline the diagnostic process by potentially reducing the need for more invasive procedures but also serve as effective tools for monitoring disease progression and evaluating treatment responses in patients with neurodegenerative conditions.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The neurofilament light chain (NfL) test is indicated for the assessment of various neurodegenerative disorders. The following conditions are explicitly associated with the use of this biomarker:

  • Alzheimer's Disease - NfL levels can indicate neuronal damage associated with this progressive neurodegenerative disorder.
  • Multiple Sclerosis - Elevated NfL levels may reflect axonal degeneration in patients suffering from this autoimmune condition.
  • Frontotemporal Dementia - The test can help in identifying neuronal injury linked to this form of dementia.
  • Amyotrophic Lateral Sclerosis - NfL serves as a marker for neuronal degeneration in this motor neuron disease.

2. Procedure

The procedure for testing neurofilament light chain (NfL) involves several key steps to ensure accurate measurement of this biomarker. The following procedural steps are outlined:

  • Sample Collection - Blood plasma or cerebrospinal fluid (CSF) is collected from the patient. For plasma samples, a venipuncture is performed to draw blood, while CSF is obtained through a lumbar puncture, which involves inserting a needle into the spinal canal.
  • Sample Processing - Once collected, the samples are processed to separate the plasma or CSF from cellular components. This may involve centrifugation to ensure that only the liquid portion is analyzed for NfL levels.
  • Assay Testing - The processed samples are subjected to a specific assay designed to detect and quantify the levels of neurofilament light chain. This assay utilizes advanced techniques to ensure sensitivity and specificity in measuring NfL concentrations.
  • Result Interpretation - After the assay is completed, the results are analyzed and interpreted by qualified healthcare professionals. Elevated NfL levels are correlated with neuronal injury and can provide insights into the presence and progression of neurodegenerative diseases.

3. Post-Procedure

Post-procedure care for patients undergoing NfL testing is generally minimal, especially for blood plasma collection. Patients may experience slight discomfort or bruising at the venipuncture site, which typically resolves quickly. In the case of CSF collection, patients may be advised to rest and hydrate adequately to minimize the risk of post-lumbar puncture headache. Follow-up appointments may be scheduled to discuss the results of the NfL test, and further diagnostic or therapeutic measures may be considered based on the findings. Continuous monitoring of NfL levels can be beneficial in assessing disease progression and response to treatment in patients diagnosed with neurodegenerative disorders.

Short Descr ASSAY NEURFLMNT LIGHT CHAIN
Medium Descr ASSAY NEUROFILAMENT LIGHT CHAIN
Long Descr Neurofilament light chain (NfL)
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Conditionally packaged laboratory tests
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) none
MUE Not applicable/unspecified.
Date
Action
Notes
2025-01-01 Added Code Added.
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