Diagnosis of COVID-19 from lower airway sampling after negative nasopharyngeal swab

Roddy, J. T.; Benn, B. S.; Lwin, P. E.; Kutty, R.; Yelisetty, A.; Darisetty, S.; Kurman, J. S.

Background: False negatives in nasopharyngeal swab testing for coronavirus disease 2019 (COVID-19) are a concern due to implications of a missed diagnosis on medical decision making and transmission risk. We aimed to characterize the presentation of patients diagnosed with COVID-19 on lower airway sampling following negative nasopharyngeal swab. Methods: We performed a retrospective observational study to identify COVID-19 patients in whom nasopharyngeal swab testing was negative. Characteristics of patients were collected including demographics, presenting symptoms, and number of false negatives prior to diagnosis. Results: We identified 8 patients in whom COVID-19 diagnosis was assisted by lower airway sampling following between 1 and 4 negative nasopharyngeal swabs. While presenting characteristics of such patients were non-specific, we identify those with negative nasopharyngeal testing on initial presentation versus later in illness, who subsequently tested positive on lower airway sampling. Conclusions: Presentations of patients with COVID-19 in whom nasopharyngeal swab is negative are non-specific. A high degree of clinical suspicion is required in approaching patients with persistent, unexplained respiratory symptoms given the high prevalence of COVID-19. It is imperative to correctly identify patients positive for COVID-19, and lower airway sampling with tracheal aspirate or bronchoalveolar lavage (BAL) may be of value in cases of high suspicion by expediting the diagnosis, though further study is required. © Journal of Public Health and Emergency. All rights reserved.