Real-World Laboratory Analysis of Molecular Biomarkers in Multiple Sclerosis Centers in Central-Eastern European Coun-tries Covering 107 Million Inhabitants

A multicenter molecular biomarker survey was conducted in Multiple Sclerosis (MS) cen-ters across Central-Eastern European countries, encompassing a population of 107 mil-lion. Our aim was to provide a "snapshot" for future studies investigating the use of mo-lecular biomarkers in MS. A self-report questionnaire was distributed via email to MS centers in seven Central-Eastern European countries (Croatia, Czech Republic, Poland, Romania, Serbia, Slovakia, and Slovenia) and to four reference centers (two in Austria, one in Germany, and one in Denmark), focusing on cerebrospinal fluid (CSF) analysis and molecular biomarkers in MS. Responding centers routinely request CSF oligoclonal band (OCB) testing in suspected MS cases, although no consensus exists on the number of CSF-restricted bands required to define OCB positivity, either within or between countries. More than half of the surveyed centers in the Czech Republic, Slovakia, Slovenia, and the reference centers request Kappa Free Light Chain (κFLC) testing in patients with suspected MS. Neurofilament Light Chain (NfL) is frequently used as a molecular biomarker for MS in Romania, Slovakia, and the reference centers. In summary, besides the use of CSF-specific OCBs there is no consensus among the surveyed countries regarding the use of molecular biomarkers in MS.