A Laboratory Comparison of Immunofluorescent Assay and Polymerase Chain Reaction (PCR) Methods for Detection of Pneumocystis jirovecii in Bronchoalveolar Lavage

Pneumocystis jirovecii is one of the most common causative agents of Pneumocystis pneumonia (PCP) in immunocompromised patients. Reliable and rapid laboratory method for detection of the organism is crucial for diagnosis of PCP. In this study, the evaluation of detection techniques for Pneumocystis jirovecii in bronchoalveolar lavage (BAL) was performed. Immunofluorescent assay (IFA), single-step polymerase chain reaction (single-step PCR) and nested polymerase chain reaction (nested PCR) methods were compared.  This study was carried on sixty samples of BAL, from patients sent to the Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University. Twenty-three of the samples (38.3%) were found to be positive by IFA. Twenty-five of them (41.6%) were found to be positive by PCR, and 56 of them (93.3%) were found to be positive by nested PCR. As a result, the single-step and nested PCR, which are rapid and reliable diagnostic tests, can be used for the screening detection of this organism.