An overview of the laboratory diagnosis of Pneumocystis jirovecii pneumonia

ABSTRACT Pneumocystis jirovecii ( P. jirovecii ) is a fungal pathogen associated with significant morbidity in immunocompromised patients, including both HIV- and non-HIV-infected patients. The nonspecific clinical and radiological presentation makes clinical diagnostic challenging, emphasizing the need for accurate laboratory diagnostic tests. However, P. jirovecii does not grow in routine culture media, which presents diagnostic challenges in the laboratory as well. Recent publications from the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium continue to rely on direct detection of P. jirovecii organisms in tissues and respiratory samples to define proven P. jirovecii pneumonia (PCP) even as the sensitivity of these methods are lower. Novel, standardized methods are needed to improve the clinical and laboratory diagnosis and management of PCP. This minireview provides an overview of current diagnostic tests for PCP and emerging applications that aim at filling existing diagnostic gaps and providing more accurate and less invasive diagnoses for this significant disease.