Before prescribing an antibiotic in CAP, specific risk factors for a poor prognosis need to be assessed. These include epidemiological factors-for example, is the patient from a nursing home, do they have a history of poor compliance or substance abuse-factors which are associated with an increased likelihood of a Gram-positive infection. Other poor prognostic factors include very young or elderly patients, the presence of co-morbidity such as malignancy, Chronic Obstructive Pulmonary Disease (or COPD) and diabetes. When these poor prognostic indicators are present, the physician may need to consider initiating an antibiotic with a wide spectrum of activity or combined therapy. It has been shown in Legionella that the results of the urinary antigen tests are related to outcome.