The NfL (neurofilament light chain) progression marker in the ALS app

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Why is the biomarker NfL important for people with ALS?

The value of the biomarker Neurofilament light chain (NfL) in the blood is suitable for assessing the progression and therapy of ALS. A high blood serum NfL value is often associated with a higher speed in the progression of ALS symptoms. Two recent publications in March this year in the international journals. European Journal of Neurology, und Muscle and Nerve impressively show a correlation between the concentration of NfL in the blood and the disease course of ALS with and without drug therapy (Tofersen)

Display of the NfL analysis results in the ALS app
The inclusion of the biomarker NfL in the estimation of ALS progression is an innovation and part of a research program realized by the ALS Outpatient Clinic of the Charité and other specialized ALS centers.

The NfL analysis results from the research program are displayed in a progress chart in the ALS mobile app. In the ALS app, the NfL chart is located on the “History” page between the ALSFRS history chart and the vital signs.

NfL-Diagramm in der ALS-App

The NfL diagram in the ALS app. The normal range of NfL serum concentrations is shown in color (light blue). The steps in the normal range result from the age-dependent increase in NfL serum concentrations. The level of the NfL serum concentration (in picograms per milliliter, pg/mL) can be read from the left scale

Infotext NfL in der ALS-App

NfL can also be detected at lower concentrations in healthy people. However, in the course of life - even in healthy individuals - the NfL level increases. The normal range of NfL serum concentrations is described in the info text behind the ? symbol.

Research project “NfL in ALS”.

The NfL analysis is not performed as in a “routine laboratory”, but within the framework of a scientific project, the study „NfL bei der ALS“. In the study, samples from different ALS centers are first collected and then analyzed. This often results in a delay. Once the analysis is complete, the data for those patients who have a consent form for ambulance partners is displayed in the ALS app in the progress chart.

The function in the ALS app can be used by patients who participate in the NfL-ALS study and APST at the same time. The parallel participation in APST is necessary for the presentation of results in the ALS-App, as the ALS-App is not a formal part of the NfL-ALS study.

What should be taken into account when displaying the NfL values?

In the progression diagram, the individual NfL values in the blood are displayed in the course of the disease as a function of age. The age-dependent display serves as an orientation, since the NfL value in the blood increases with age. Therefore, based on studies, thresholds have been agreed upon above which the NfL level is pathological in ALS. The threshold between normal and pathological NfL is displayed in the ALS app.

For patients participating in the ALS-NfL study, expert medical interpretation of the findings is necessary. Various medical factors such as age and onset of disease must be taken into account. The assessment of the NfL value takes place in personal doctor-patient contact in an NfL study center.

The biomarker NfL

NfL is a nerve cell-specific protein that is released into the blood when the nerve cell is damaged. NfL can be detected in blood serum and cerebrospinal fluid (CSF) by special analytical methods.The NfL-ALS study has shown that there is a close correlation between the NfL concentration in the blood and disease progression: patients with a high ALS progression have significantly increased NfL levels, while those affected with a slow and/or long ALS course have a lower NfL increase. NfL is thus – in addition to other important factors (such as body weight, respiratory power, and cough thrust) – one of several prognostic factors for the expected course of the disease.
For more information about NfL and the ALS app, visit:

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Your Ambulance Partner Team