FUNGAL testing was infrequent in outpatient community-acquired pneumonia and small numbers were diagnosed with endemic mycoses.
Low Testing Rates for Outpatient Community-Acquired Pneumonia
Diagnostic testing is often required to distinguish blastomycosis, histoplasmosis, or coccidioidomycosis from other causes of community-acquired pneumonia, yet real world data on testing patterns across the U.S. have been limited. A retrospective cohort study used 2017 to 2023 commercial health insurance claims from the Merative MarketScan Commercial and Medicare Database to evaluate how often adult outpatients with unspecified community-acquired pneumonia received fungal testing, and how often those tested were diagnosed with an endemic mycosis.
Among 573,994 adults with unspecified community-acquired pneumonia managed in outpatient settings, 25,822 underwent diagnostic testing for blastomycosis, histoplasmosis, or coccidioidomycosis, representing about 5% of the cohort. Testing also tended to occur after repeat encounters, with a median of three health care visits following the initial community-acquired pneumonia diagnosis.
Endemic Mycoses Diagnoses After Testing
Among patients who were tested, 755, or roughly 3%, received a diagnosis code for blastomycosis, histoplasmosis, or coccidioidomycosis. The analysis also identified clinical features linked with a higher likelihood of diagnosis after testing.
For coccidioidomycosis, rash was associated with the largest increase in likelihood of diagnosis. Lymph node enlargement, muscle aches, and chest pain were also associated with higher odds. Receipt of antibiotics from more than one class was linked with a higher likelihood of coccidioidomycosis diagnosis as well, which may reflect persistent symptoms or lack of improvement with initial therapy.
For histoplasmosis, autoimmune inflammatory disease and chest pain were associated with higher odds of diagnosis, while abnormal weight loss showed the strongest association, suggesting that systemic features may help differentiate histoplasmosis from other outpatient community-acquired pneumonia presentations.
Clinical Relevance
The authors conclude that testing rates for these endemic mycoses were low in many U.S. locations. They suggest that improved recognition and earlier consideration of fungal etiologies in outpatient community-acquired pneumonia could reduce repeat health care visits and potentially limit unnecessary antibiotic exposure, with downstream benefits for patient outcomes.
Reference: Benedict K et al. Blastomycosis, Histoplasmosis, and Coccidioidomycosis in Outpatient Community-Acquired Pneumonia. JAMA Network Open. 2026;9(1):e2553965.
