Clinical validation of the fluorescent immunochromatographic strip test FICT with patients infected with respiratory syncytial virus (RSV). The FICT was performed with human specimens collected from patients infected with RSV (n = 10) and patients with other diseases (n = 50). (A) The cut-off value was determined based on the receiver operating characteristic (ROC) curve, representing the sensitivity, specificity, and 95% confidence interval (CI). (B) Based on ROC curve analysis, 44.21 was determined as the cut-off value to differentiate RSV infection in a clinical study. This cut-off value for the detection of RSV was applied to determine whether each sample was positive or negative for the presence of the virus, and is indicated in the graph as a dotted line. Nine RSV infection cases showed test line/control line (TL/CL) values that were higher than the threshold value. The non-RSV-infected control group (n = 50) had no false-positive cases. (C) The sensitivity, specificity, and 95% confidence interval (CI) of the assays were computed for the diagnosis of RSV infection.