Equine pNF-H, phosphorylated neurofilament ELISA

Equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM) is one of the top three causes of spinal ataxia in horses. It is characterized by incoordination that typically develops in foals 6 to 12 months of age. Equine neuroaxonal dystrophy and EDM are clinically indistinguishable, with EDM being a more advanced form of the disease. Although a genetic susceptibility to eNAD/EDM is highly suspected, and the role of vitamin E deficiency during early life well supported, the etiology of eNAD/EDM remains unknown.

Until now, the only way to definitively diagnose eNAD/EDM was through postmortem histologic evaluation of the brainstem and spinal cord. This biomarker test represents the first diagnostic antemortem testing available for eNAD/EDM. This test measures a biomarker of axon damage called phosphorylated neurofilament heavy subunit (pNF-H) in serum and/or cerebrospinal fluid (CSF) by ELISA capture assay. Serum and CSF pNF-H testing for eNAD/EDM has higher sensitivity in horses < 5 years of age as compared to older horses.

Forms and Interpretation


  • What about EPM?
    It is important to know a horse’s EPM status prior to running the pNF-H biomarker assay. If the horse is negative for EPM, a diagnosis of eNAD or CVCM is possible and may be further refined with the pNF-H test. Diagnostics for EPM should ideally be run on the same CSF sample and EPM excluded before proceeding with the pNF-H testing.
  • What about the effect of red blood cell contamination on CSF results?
    Our studies used CSF samples with <500 red cells (RBCs)/mL. The effect of larger numbers of red cells on pNF-H test results has not been assessed. Therefore, any CSF sample with RBC contamination >500 RBCs should not be submitted for pNF-H testing.


Effective for samples received by the lab July 1, 2021 - June 30, 2022.

  • pNF-H - $84/sample*
  • *Prices subject to change without notice.  Updated 6/29/2021.

Submission information

  • Check the test(s) requested on the sample submission form.
  • Number and type of samples included in submission
  • Sample collection date
  • Patient name, breed, sex, and age
  • Patient’s owner name and address
  • Clinic/hospital name and complete mailing address
  • Veterinarian’s name
  • Phone number, fax number and email
  • Pertinent clinical history

Sample Processing & Shipping

  • Blood Processing: Spin and separate serum from red cells. Place serum in a new, clean tube. Serum separator tubes are not recommended, as the separator becomes dislodged during shipping, allowing red cells and serum to mix. A handling fee will be assessed for unprocessed or improperly processed blood samples.
  • CSF processing: Collect CSF in a clean red top tube. DO NOT spin CSF samples.
  • We recommend submitting both serum and CSF for most accurate results.
  • Send all samples with a cold pack / ice pack.
  • Ship overnight by FedEx (do not use USPS), Monday-Thursday only. Do not ship on Fridays, weekends or national holidays.
  • Our FedEx Reduced Price Shipping Program is available for for veterinarians and veterinary clinics. FedEx is the preferred shipping method for overnight delivery. Please do not ship using USPS; USPS mail is delivered to a central campus location before being distributed to our labs, delaying transit time of sensitive laboratory samples.
  • Ship to:
    UC Davis VMTH
    Central Laboratory Receiving, Rm 1033

    1 Garrod Drive
    Davis, CA  95616-8747

Biological samples submitted to the VMTH Clinical Diagnostic Laboratories may be used for VMTH teaching and research purposes consistent with the mission of the University.

References and additional information

Finno Laboratory, UC Davis School of Veterinary Medicine

Edwards L, Donnelly CG, Reed S, Valberg SJ, Johnson AL, Finno CJ. Serum and cerebrospinal fluid phosphorylated neurofilament heavy chain concentrations in equine neurodegenerative disorders. Equine Vet J. 2021 May 9. doi: 10.1111/evj.13452.

Hales EN, Esparza, C, Peng, S, Dahlgren, AR, Peterson, JM, Miller, AD, Finno, CJ. Genome-Wide Association Study and Subsequent Exclusion of ATCAY as a Candidate Gene Involved in Equine Neuroaxonal Dystrophy Using Two Animal Models. Genes. 2020;11:82.

Burns EN, Finno CJ. Equine degenerative myeloencephalopathy: prevalence, impact, and management. Vet Med (Auckl). 2018;9:63-67.

Finno, C., Estell, K., Winfield, L., Katzman, S., Bordbari, M., Burns, E., et al. (2018). Lipid peroxidation biomarkers for evaluating oxidative stress in equine neuroaxonal dystrophy. Journal of veterinary internal medicine. 2018;32(5):1740-1747.

Finno, CJ, Valberg, SJ, Shivers, J, D’Almeida, E, Armién, AG. Evidence of the Primary Afferent Tracts Undergoing Neurodegeneration in Horses With Equine Degenerative Myeloencephalopathy Based on Calretinin Immunohistochemical Localization. Veterinary Pathology 2016;53(1): 77-86.

Finno, CJ, Estell, KE, Katzman, S, Winfield, L, Rendahl, A, Textor, J, Bannasch, DL, Puschner, B. Blood and Cerebrospinal Fluid α-Tocopherol and Selenium Concentrations in Neonatal Foals with Neuroaxonal Dystrophy. Journal of Veterinary Internal Medicine 2015; 29:1667–1675.

Finno CJ, Famula T, Aleman M, Higgins RJ, Madigan JE, Bannasch DB. Pedigree analysis and exclusion of α-tocopherol transfer protein as a candidate gene for neuroaxonal dystrophy in the American Quarter horse. J Vet Intern Med. 2013;27(1):177-85.

Finno CJ, Valberg SJ. A comparative review of vitamin E and associated equine disorders. J Vet Intern Med. 2012;26(6):1251-66.

Aleman M, Finno CJ, Higgins R, Puschner B, Gericota B, Gohil K, LeCouteur RA, Madigan JE. Evaluation of epidemiological, clinical, and pathological features of neuroaxonal dystrophy in Quarter Horses; J of Vet Med Assoc. 2011;239(6):823-833.

Finno CJ, Higgins R, Aleman M, Ofri R, Hollingsworth S, Bannasch DL, Riley C, Madigan JE. Equine Degenerative Myeloencephalopathy in Lusitano horses. J Vet Inter Med. 2011;25(6):1439-46.

Using Diet to Manage Neuromuscular Disorders”, UC Davis Center for Equine Health Horse Report, Spring 2020

UC Davis Center for Equine Health Horse Report, Fall 2018, The Vitamin E issue (pdf)

Neuroaxonal dystrophy / equine degenerative myelopathy - YouTube video with Dr. Finno for thehorse.com