Is NF-L in CSF Lumbal Puncture a reliable BioMarker?
I dare to ask this question over here in the forum, not to bother someone but because I know there is a lot of knowledge in this community.
My story started in August 2021. My leg felt a little weird, and weak, and a few weeks later I started to have widespread fasciculations in my entire body. I got trouble swallowing, coughing and my upperarms, especially my right on became very small as my muscles (coming from my shoulder) were wasted. I also noticed some weakness over there.
I was send to a neurologist who did a basic neurologic Exam, and an EMG of the four limbs and the tongue. This came back clean. Also bloodwork, CT’s and MRI (Spine and Brain) were done, nothing wrong.
Because my symptoms were still there and I’m pretty scared the neurologist proposed to do a lumbal puncture with some kind of Neurofilament marker. This was done 6 weeks after my very first symptoms.
The results came back extremely low
NFL : 134 pg/ml. (must be lower than 1227)
PNH : 115 pg/ml (must be lower than 750)
Based on this results my neurologist closed the case. No ALS!
Do I have to search for a second opinion in this case, because I still got all the symptoms?
Is this biomarker test a reliable test when done this early in the process? Or is it possible that the puncture was done so early that Neurofillaments were not elevated yet? After all, it was done 6 weeks after my very first subtile symptoms.
The values a looking also extremely low to me, lower than normal.. Maybe something went wrong in the test, which seems impossible.
I want to thank everybody already for all the comments on my post.
Log in to reply.