Statistical analysis was performed using a rank sum test for paired samples (Wilcoxon) for which p values below 0.05 were considered significant. EFNS counting rule to the gold standard in visualizing and quantifying the epidermal TTA-Q6 nerve fiber network. As the LDT requires the use of 16?m tissue sections, a higher incidence of intra-epidermal nerve fiber fragments and a lower incidence of secondary branches were detected. Nevertheless, the LDT showed excellent concordance with the gold standard method. Next, the diagnostic performance and yield of the LDT were explored and challenged to the gold standard using skin punch biopsies of capsaicin treated subjects, and patients with diabetic polyneuropathy. The LDT reached good agreement with the gold standard in identifying small fiber neuropathy. The reduction of section thickness from 50 to 16?m resulted in a significantly lower visualization of the three-dimensional epidermal nerve fiber network, as expected. However, the diagnostic performance of the LDT was adequate as characterized by a sensitivity and specificity of 80 and 64?%, respectively. Conclusions This study, designed as a proof of principle, indicated that the LDT is an accurate, robust and automated assay, which adequately and reliably identifies patients presenting with small fiber neuropathy, Mouse monoclonal to CD4/CD38 (FITC/PE) and therefore has potential for use in large scale clinical studies. IENF; IENF_Si; IENF_Br; IENF_F; IENF_FSi; IENF_FBr. (20?m) LDT method validation Besides the confirmation that the anti-human PGP9.5 antibody accurately detects its target, we established reference intervals and defined LDTs discrepancies in reference to the GS-EFNS (LDT modifications to the GS-EFNS counting rule) on biopsies obtained from healthy subjects. Diagnostic yield and diagnostic performance (analytical sensitivity and specificity) were explored by plotting the plausibility of false positives (specificity) and true positives (sensitivity). The closer the ROC curve approaches the true positive axis, the better the performance of the LDT (see Statistics section). The examination of the inter-slide stability of the GS-EFNS and LDT was included since this could highlight the need for a minimum number of serial slides to be examined. For each subject and each staining method three serial slide measurements were performed by one observer (M1, M2, and M3). In order to estimate the reliability of results obtained by independent observers, individual counts for the different parameters were compared after automated staining of 12 randomly selected samples. Statistics Method comparison of the LDT and GS-EFNS was performed using BlandCAltman analysis [25]. To prove a good agreement between the two techniques the values should be lumped near the 0-difference line. Statistical analysis was performed using a rank sum TTA-Q6 test for paired samples (Wilcoxon) for which p values below 0.05 were considered significant. Statistical analysis for assessing the diagnostic yield of the LDT compared to conventional diagnostic tools was performed as described before [19]. To explore if data obtained using the EFNS advised method can serve as the gold standard to define the diagnostic performance of the LDT on the selected biopsies, a one-way analysis of variance was performed (ANOVA). This allowed confirming that mean values were significantly different between control and SFN groups. The diagnostic performance of the LDT was estimated by the area under the receiver operating characteristic curve (ROC) with 95?% confidence interval for sensitivity and specificity using De Longs test. Inter-observer agreement was evaluated by determining intra-class correlation (ICC) for all parameters using the TTA-Q6 same raters for all measurements and consistency as type. All analyses were performed using MedCalc? v12.3.0.0 statistical software. Finally, a power calculation was carried out to determine the statistical power of this study and the optimal sample size for a future study using software package R, version 3.1.2 [26]. We performed this analysis using data for the total linear density of epidermal nerve fibers. Results Accuracy of the anti-human PGP9.5 antibody The accuracy of the rabbit polyclonal anti-human PGP9.5 antibody was confirmed by western blot analysis on cell lysates from U87 and A549 cell lines. For both cell lines the antibody showed a band at a molecular weight of approximately 25?kDa (Fig.?2a), confirming the recognition of PGP9.5 (27?kDa). In addition, III-tubulin, a nerve and langerhans cell-specific marker, co-localized in all PGP9.5 immunoreactive structures of the epidermis (Fig.?2b), confirming the accuracy of the antibody. Open in a separate window Fig.?2 Evaluation of antibody accuracy. a Western Blot analysis of A549 and U87 cell lines using the rabbit polyclonal anti-human PGP9.5 antibody (Nerve fiber; Langerhans-cells. (20?m) Assessment of IENF and nerve fiber branching density in skin biopsies of healthy volunteers** A significant difference existed in the ability of the LDT assessing IENF compared to the gold TTA-Q6 standard (p? ?0.001, mean difference 5.8 IENF/mm), especially with regard to IENF_Br (p? ?0.001, mean difference 5.7 IENF_Br/mm) (Table?1). For.