False-Negative Nasopharyngeal Swab RT-PCR Assays in Typical COVID-19: Role of Ultra-low-dose Chest CT and Bronchoscopy in Diagnosis

Marando, Marco; Tamburello, Adriana; Gianella, Pietro

On 11 March 2020, the WHO declared COVID-19 a pandemic and global health emergency. We describe the clinical features and role of ultra-low-dose chest computed tomography (CT) and bronchoscopy in the diagnosis of coronavirus disease (COVID-19). In our patient, who was highly suggestive clinically and radiologically for COVID-19, we had two false-negative results for nasopharyngeal and oral swab reverse-transcriptase polymerase chain reaction (RT-PCR) assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Eventually, we confirmed the diagnosis using bronchoscopy and bronchoalveolar lavage (BAL). LEARNING POINTS: Clinical and laboratory findings in COVID-19 are unspecific. Chest CT has a diagnostic sensitivity comparable to nasopharyngeal swab RT-PCR assay but lacks specificity. RT-PCR assays on biological specimens, particularly nasopharyngeal swabs, are considered the diagnostic gold standard. Bronchoscopy and bronchoalveolar lavage can help confirm the diagnosis and should be performed in patients in whom diagnostic-driven treatment for COVID-19, such as tocilizumab or remdesivir, is being considered.