Since no laboratory test is specifi c to IPF exacerbations, most tests are performed to exclude treatable causes of deterioration and to document the severity of the exacerbations. Th e standard laboratory work-up should include all necessary tests for the investigation of a critically ill patient with impeding ALI/ARDS of unknown etiology. ALI and ARDS criteria (arterial partial pressure of oxygen/fraction of inspired oxygen [PaO 2 /FiO 2 ] of less than 300 and less than 200, respectively) should prepare the clinician for the possibility of mechanical support. Accurate diagnosis in IPF exacerbations requires bronchoalveolar lavage (BAL) to exclude infection or alternative diagnoses; BAL is best performed before mechanical support or immediately afterwards [2] . Perform ing lung biopsy could be justifi able when facing a disease with grave prognosis but bears an increased risk for postsurgical complications and should be individual ized to each patient [2] .