d-Dimer was measured (Liatest D-DI quantitative automated latex system; Diagnostica Stago; Asnières-sur-Seine, France) on the day that the specimen was collected (STA; Diagnostica Stago). A value of > 500 ng/mL was considered to be a positive d-dimer level (ie, the cutoff level used in our hospital in the diagnosis of venous thromboembolic disease, which is equal to the upper limit of the reference range). Patients also underwent standard evaluation that included medical history, physical examination, CXR, and ECG. Blood cell counts, C-reactive protein measurement, and prothrombin time also were measured. Two blood samples for culture and a sputum sample for Gram staining and culture were collected before the antibiotic treatment was begun when the patient could expectorate normally. In the first 24 to 48 h, antigen detection tests for pneumococcus (Now Streptococcus pneumoniae Urinary Antigen Test; Binax; Portland, ME) and Legionella (Now Legionella pneumophila Urinary Antigen Test; Binax) in urine were performed, and a serum sample was drawn to complete the etiologic diagnosis, using it together with the sample collected after the first 4 weeks to make the serologic diagnosis for L pneumophila, Mycoplasma pneumoniae, Chlamydia pneumoniae, Coxiella burnetii, respiratory syncytial virus, adenovirus, influenza A, influenza B, parainfluenza 1, parainfluenza 2, and parainfluenza 3.