Performance of Laboratory Testing in Culture-Confirmed Blastomycosis: A Retrospective Study

Area of Science:

• Mycology
• Infectious Diseases
• Clinical Diagnostics

Background:

• Blastomycosis is a serious fungal infection endemic to North America.
• Accurate and timely diagnosis is critical for effective treatment and patient outcomes.
• Diagnostic challenges exist, particularly in cases with negative initial test results.

Purpose of the Study:

• To evaluate the effectiveness of various diagnostic methods for blastomycosis.
• To assess the performance of urine antigen testing in different disease presentations.
• To identify essential complementary diagnostic tools for antigen-negative blastomycosis cases.

Main Methods:

• Retrospective analysis of 51 culture-confirmed blastomycosis cases.
• Evaluation of diagnostic modalities including urine antigen testing, antibody testing (enzyme immunoassay), pathology, and fungal culture.
• Analysis of diagnostic performance across different blastomycosis disease types.

Main Results:

• Urine antigen testing showed variable sensitivity depending on the type of blastomycosis.
• Antibody testing, pathology, and fungal culture were vital for diagnosing cases where urine antigen tests were negative.
• A multimodal diagnostic strategy proved essential for comprehensive case identification.

Conclusions:

• A combination of diagnostic approaches is necessary for optimal blastomycosis diagnosis.
• Reliance on a single test, such as urine antigen testing, may lead to missed diagnoses.
• Integrating serological, pathological, and microbiological methods ensures accurate identification of blastomycosis.