Calculation of the kappa statistic. The kappa statistic 47 was calculated using the following terms. True positive (TP) is the number of analytes predicted to be reactive that is experimentally reactive where false positive (FP) is the number of analytes predicted to be reactive that are not reactive. Similarly, true negative (TN) is the number of analytes predicted to be unreactive that are truly unreactive and false-negative (FN) is the number of analytes predicted to be unreactive that are experimentally reactive. Using these definitions, accuracy (𝑃 = ) is defined using equation (4).