Diagnosing Blastomycosis: A Review of Laboratory Methods and Clinical Utility

Blastomycosis, caused by dimorphic fungi of the Blastomyces genus, is endemic to regions in North America, including the Great Lakes and other parts of Canada and the United States of America. The infection primarily occurs through the inhalation of airborne conidia from contaminated soil and decaying organic matter. Pulmonary involvement is most common, but dissemination to other organs such as the skin and bones can occur, especially in immunocompromised individuals. Diagnosis is challenging due to its clinical overlap with other diseases. Culture remains the gold-standard diagnostic method, but is time-consuming, with sensitivity ranging from 66.4% to 86%. Tissue histopathology offers quicker results but has sensitivities ranging from 36% to 85%. Antigen detection assays show high sensitivity from 76.3% to 91.3% but suffer from cross-reactivity with other fungi. PCR methods offer high specificity, with sensitivity ranging from 67.6% to 100%. In immunocompromised patients, blastomycosis is often more severe, with a mortality rate exceeding 30%. Multi-modal diagnostic approaches are crucial for accurate detection and management.