Legionella Pneumonia Undetected by Repeated Urinary Antigen Testing With Ribotest® Legionella

This report presents a patient with <i>Legionella</i> pneumonia (LP), initially presented with fever and mild hypoxemia, with subsequent progression to severe pneumonia during hospitalization. Despite multiple negative urinary antigen tests using Ribotest^® <i>Legionella</i>, the diagnosis was confirmed via the loop-mediated isothermal amplification method of lower respiratory tract secretions. This case highlights the diagnostic limitations of Ribotest^® <i>Legionella</i> and emphasizes the importance of a comprehensive diagnostic strategy, incorporating nucleic acid amplification tests or culture in suspected patients with LP. Early recognition of these diagnostic challenges is critical for optimizing patient outcomes.