Moreover, with the exception of CRP in pneumothorax and empyema, in which significant increases can be seen, CRP, pleural fluid CRP, and gradient CRP have been proposed as markers for the discrimination of Uncomplicated Parapneumonic Effusion (UCPPE) from Complicated Parapneumonic Effusion (CPPE) [317]. The gene discussed is CRP; the disease is pneumothorax.