The diagnosis of peripheral neuropathies can be challenging with consequent difficulties in patients’ management. The aim of this study was to explore the current diagnostic role of sural nerve biopsy and to compare pathological findings with serum neurofilament light chain levels (NfL) as biomarkers of axonal damage. We collected demographic, clinical, and paraclinical data of patients referred over 1 year to the Neurology Unit, University of Verona, Italy, to perform nerve biopsy for diagnostic purposes, and we analyzed NfL levels in available paired sera using a high sensitive technique (Quanterix, Simoa). Eighty-two patients were identified (37.8% females, median age 65.5 years). Neuropathy onset was frequently insidious (68.3%) with a slowly progressive course (76.8%). Lower limbs were usually involved (81.7%), with a predominance of sensory over motor symptoms (74.4% vs 42.7%). The most common neuropathological findings were a demyelinating pattern (76.8%), clusters of regenerations (58.5%), and unmyelinated fibers involvement on ultrastructural evaluation (52.4%). A definite pathological diagnosis was achieved in 29 cases, and in 20.7% of patients, the referral clinical diagnosis was modified. Coexistent hematological conditions and hepatitis were diagnostic confounding factors (p = 0.012 and 0.034, respectively). In the analyzed paired sera (n = 37), an inverse despite not significant relationship between NfL values and fiber density was observed (Spearman’s rho − 0.312, p = 0.056). In addition, we noted increased serum NfL values of patients with active axonal degeneration. Nerve biopsy remains a useful diagnostic investigation to achieve a correct diagnosis and guide patients’ management in selected cases of peripheral neuropathy. Serum NfL is an accessible and potential valuable marker of axonal damage in these conditions.

周围神经病变的诊断可能具有挑战性，从而给患者的治疗带来困难。这项研究的目的是探讨腓肠神经活检的当前诊断作用，并将病理结果与血清神经丝轻链水平（NfL）作为轴突损伤的生物标志物进行比较。我们收集了转诊至意大利维罗纳大学神经病学部门一年以上的患者的人口统计学，临床和临床前数据，以进行神经活检以用于诊断目的，并使用高灵敏度技术（Quanterix分析了可用配对血清中的NfL水平，Simoa）。确定了82例患者（女性37.8％，中位年龄65.5岁）。神经病发作通常是隐匿性的（68.3％），病程缓慢（76.8％）。下肢通常受累（81.7％），感觉优于运动症状（74.4％比42.7％）。最常见的神经病理学发现是脱髓鞘样变（76.8％），再生簇（58.5％）和无髓鞘纤维参与超微结构评估（52.4％）。明确的病理诊断为29例，有20.7％的患者对转诊临床诊断进行了修改。血液病和肝炎并存是诊断的混杂因素（p 分别为0.012和0.034）。在分析的配对血清（n  = 37）中，尽管NfL值与纤维密度之间没有显着关系，但观察到相反的结果（Spearman的rho-0.312，p  = 0.056）。此外，我们注意到活动性轴索变性患者血清NfL值升高。神经活检仍是一项有用的诊断研究，可在特定的周围神经病变病例中实现正确的诊断并指导患者的治疗。在这些情况下，血清NfL是轴突损伤的可及且潜在的有价值的标志物。