Neurofilament light (NfL)

Test Mnemonic


CPT Codes

  • 83520 - QTY (1)


  • NfL, Plasma

Performing Laboratory


Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
1 mLPlasmaEDTA (Lavender) AmbientPatient should avoid biotin consumption for at least 72 hours prior to collection. Separate plasma and transfer to standard aliquot tube.

Minimum Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
0.7 mL     


Environmental Condition Description
Ambient14 days
Refrigerated14 days
Frozen14 days (3 freeze/thaw cycles)

Days Performed


Turnaround Time

2 - 4 days


Name Description
Electro Chemiluminescence Immunoassay (ECLIA) 

Reference Range

Neurofilament Light Chain, Plasma
Sex Age From Age To Type Range Range Unit
   Years4 YearsNormal< 1.97pg/mL
 5 Years9 YearsNormal< 1.64pg/mL
 10 Years14 YearsNormal< 1.43pg/mL
 15 Years19 YearsNormal< 1.60pg/mL
 20 Years29 YearsNormal< 1.65pg/mL
 30 Years39 YearsNormal< 1.88pg/mL
 40 Years49 YearsNormal< 2.14pg/mL
 50 Years59 YearsNormal< 3.79pg/mL
 60 Years69 YearsNormal< 4.62pg/mL
 70 Years79 YearsNormal< 7.65pg/mL
 80 Years99 YearsNormal< 11.56pg/mL

Clinical Info

This test is used for the measurement of the level of Neurofilament Light Chain in plasma. There are significant variations in measured plasma NfL levels among different methods and labs. Care must be taken when interpreting results obtained in different studies. Direct comparisons of absolute values can only be done on the same source fluid (plasma or serum). A rise in NfL is not specific for a specific disease factor and may be caused by both neurodegenerative diseases or a head impact during sports. Results should only be used in conjunction with other clinical information when evaluating patients with neurodegeneration. Due to a lack of specificity to a particular neurodegenerative disease, its role as a diagnostic marker is limited. There are numerous demographic, life style, and comorbidity factors that potentially influence NfL levels in plasma. Variables such as exercise,2 blood volume, body mass index may impact measured plasma NfL levels. NfL levels measured in the morning are more than 10% higher than those measured in the evening. Caution should be taken in interpreting NfL levels when disease treatment induced neurological complications that can potentially impact NfL levels. Plasma NfL levels can be decreased in patients with high immunoglobulin G (IgG) levels. Higher concentrations of NfL may be found in persons with history of stroke, atrial fibrillation, myocardial infarction, chronic kidney disease, pregnancy, and diabetes. Lower concentrations of NfL may be found in individuals who are obese (BMI > or =30).