Clinical Evaluation of a (1,3)-β- d -Glucan Assay for Presumptive Diagnosis of Pneumocystis jiroveci Pneumonia in Immunocompromised Patients

(1,3)-beta-d-Glucan (BG) is a component of the Pneumocystis jiroveci cell wall. Thirty-one immunocompromised patients with pneumonia (16 with presumptive pneumocystis pneumonia [PCP] and 15 with non-PCP) were evaluated for serum BG levels. Serum from all 16 presumptive PCP patients and from 2/15 patients with non-PCP was positive for BG. Results indicate that BG is a reliable marker for diagnosing PCP.