Intraepidermal nerve fiber analysis using immunofluorescence with and without confocal microscopy

Introduction Intraepidermal nerve fiber (IENF) linear density is a reliable tool to detect small‐fiber neuropathies. In immunofluorescence, the IENF count is performed typically by computer‐assisted nerve tracing on confocal images. Alternatively, the count can be performed directly through the oculars of a standard epifluorescence microscope. We specifically compared measures obtained using the 2 methods. Methods We compared measures of IENF density in the same 50 skin samples using computer‐assisted image analysis and direct count. Results There was excellent agreement between the 2 methods. Linear regression showed a slope between paired measures virtually equal to 1 (β = 0.99). Bland–Altman analysis showed a mean difference (offset) between the measures of 0.46 ± 0.91 fibers/mm. Conclusions Direct observation with epifluorescence microscopy proved as reliable as the more time‐consuming 3‐dimensional computer‐assisted analysis of confocal digital images for determining IENF density.