Enomoto N, et al. - Researchers retrospectively studied patients (48 episodes), who were diagnosed with acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) and treated at their hospital between 1997 and 2015, to investigate whether serum ferritin is clinically important in the setting of AE-IPF. They detected significantly higher levels of serum ferritin in patients with AE-IPF, compared with baseline levels at the first diagnosis of IPF. The cut-off value 174 ng/mL for the separation of AE (area under the curve, 0.700) was demonstrated in receiver operating characteristic analysis. Positivity for anti- melanoma differentiation-associated gene 5 antibody was not detected in any of the patients. Overall, in these patients, higher serum ferritin may be associated with a worse prognosis.