The present invention relates to methods for detecting P aeruginosa infection and bacterial burden in the lungs of patients who are at risk for P. aeruginosa infections, especially including patients with Cystic Fibrosis (CF). The present method provides numerous tests (breath, blood, urine) which are readily administered to a patient that will sensitively and specifically detect the presence and extent of lung infection P. aeruginosa (both mucoid and non-mucoid), and allow monitoring of bacterial load as a parameter in monitoring treatment.
