Akagi T, et al. - In elderly patients (aged ≥ 75 years) with pneumonia acquired outside of the hospital, researchers evaluated the association between procalcitonin (PCT) and prognosis and pneumonia severity. For this investigation, they retrospectively reviewed clinical charts of all consecutive patients admitted to the hospital from October 2010 to July 2017 with primary diagnoses of community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP). In both of elderly and younger patients with pneumonia acquired outside the hospital, PCT was not an independent predictor of 30-day mortality. PCT levels, but not C-reactive protein levels, increased significantly with increasing pneumonia severity (mild, moderate, and severe) in younger and elderly patients, although the rise in elderly patients tended to be lower than in younger patients with the same severity. In elderly patients with Streptococcus pneumoniae pneumonia, PCT levels also significantly increased with increasing pneumonia severity.