CRP and idiopathic pulmonary fibrosis: Other prognostic biomarkers for patients with AE-IPF include the baseline PaO2/FiO2 (P/F) ratio at AE [16,34], low baseline FVC and diffusion lung capacity for carbon monoxide (%DLCO) [26], C-reactive protein (CRP) [34], delay before initiating therapy [26], ΔP/F ratio 2 days after commencement of treatment for AE, and ΔLDH 2 days after commencement of AE treatment [58].