ESR1 and temporal arteritis: While both the ROC-AUC analysis and sensitivity/specificity analysis at optimum cut-off values determined that ESR, CRP and platelet counts are equivalent tests with moderate utility for the diagnosis of GCA, there was in fact, only moderate agreement between the three tests in terms of the individual positive/negative classifications (agreement: 67 95% CI 63, 71; prevalence and bias adjusted kappa: 0.34, 95%CI 0.26, 0.42).