TNC and rheumatoid arthritis: To assess the specificity and sensitivity of total tenascin-C in discriminating people with RA from healthy controls, data extrapolated from the ROC curve show that using a cut-off based on the 99% or 97.5% percentile of the healthy controls, sensitivity was low (6.7 and 14% respectively), reaching 38% using a cut-off based on the 95% percentile of healthy controls (Figure 3C and Table 5).