Cystic fibrosis (CF) pulmonary exacerbations (PEx) remain underdiagnosed by CF clinicians. Serum C-reactive protein (CRP) and calprotectin are inflammatory biomarkers that have the potential to aid in the diagnosis of PEx. 19 subjects (56 stable, 46 PEx visits) from a longitudinal study were included and the diagnostic performance of absolute and fold-change CRP and calprotectin cut-offs to discriminate stable and PEx visits was assessed. Based on Youden's index, optimal absolute and fold-change thresholds to identify PEx were 9.5 mg/L (Sn 76%, Sp 73%; AUC 0.76) and 2.2-fold (Sn 50%, Sp 96%; AUC 0.78) for CRP and 8.1 mg/L (Sn 61%, Sp 79%; AUC 0.72) and 1.3-fold (Sn 57%, Sp 88%; AUC 0.74) for calprotectin. A step-wise algorithm was able to improve diagnostic performance (Sn 80%; Sp 88%). CRP and calprotectin could discriminate stable vs. PEx visits with good performance and appear promising as diagnostic biomarkers but further validation studies are required prior to implementing these diagnostic thresholds.

中文翻译：

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循环 CRP 和钙卫蛋白诊断 CF 肺加重

囊性纤维化 (CF) 肺恶化 (PEx) 仍未被 CF 临床医生诊断出来。血清 C 反应蛋白 (CRP) 和钙卫蛋白是炎症生物标志物，有可能有助于 PEx 的诊断。包括来自纵向研究的 19 名受试者（56 名稳定，46 次 PEx 访问），并评估了绝对和倍数变化 CRP 和钙卫蛋白临界值的诊断性能，以区分稳定和 PEx 访问。根据约登指数，识别 PEx 的最佳绝对阈值和倍数变化阈值为 9.5 mg/L（Sn 76%，Sp 73%；AUC 0.76）和 CRP 的 2.2 倍（Sn 50%，Sp 96%；AUC 0.78）钙卫蛋白为 8.1 mg/L（Sn 61%，Sp 79%；AUC 0.72）和 1.3 倍（Sn 57%，Sp 88%；AUC 0.74）。逐步算法能够提高诊断性能（Sn 80%；Sp 88%）。CRP 和钙卫蛋白可以区分稳定型和非稳定型。