Broncho-Alveolar Lavage for Diagnosis of Pneumocystis jirovecii Pneumonia – A Scoping Review

The diagnosis of Pneumocystis jirovecii pneumonia (PJP) in immunocompromised patients remains challenging despite the use of conventional staining techniques in bronchoalveolar lavage samples. Quantitative PCR (qPCR) has demonstrated improved diagnostic accuracy compared with traditional methods. This scoping review evaluated the diagnostic validity of conventional stains versus qPCR for PJP diagnosis in immunocompromised patients. Comprehensive searches of MEDLINE, PubMed, Cochrane Library, and CINAHL databases were conducted between April–October 2025 for studies published from 1985 onwards. A reproducible search strategy using predefined Medical Subject Headings terms and eligibility criteria was applied. Of 856 identified studies, eight met inclusion criteria for final analysis. Methodological quality was assessed using Joanna Briggs Institute critical appraisal tools. Most included studies originated from high-income countries and focused on adult populations, whereas paediatric and developing-world data were limited. Gomori methenamine silver staining showed lower sensitivity and specificity than immunofluorescence assay, while qPCR consistently demonstrated superior diagnostic performance. However, findings should be interpreted cautiously because of limited study numbers and methodological heterogeneity. Further multicentre studies are required to validate the clinical utility of qPCR in PJP diagnosis.