CXCL8 and asthma: The area under curve (AUC) for serum IL-8 level, indicative of uncontrolled asthma, was 0.816 (95% CI, 0.7605 to 0.8721; P< 0.0001), which was greater than the AUC of fractional exhaled nitric oxide (AUC, 0.711; 95% CI, 0.6057 to 0.8153; P= .0188).