Fig 1
Receiver operating characteristic (ROC) curves plotting the true-positive rate (sensitivity) in function of the false-positive rate (100-specificity) for different cutoff points of a parameter. The area under the ROC curve (AUC) measures how well a parameter can distinguish between diagnostic classes. In the asthma/CC+ class an AUC of 0.87 means that a randomly selected subject from this class has a test value larger than that for a randomly chosen subject from another class 87% of the time.