key: cord-0987270-a18lw6kf authors: Aggarwal, Deepak; Saini, Varinder title: Factors limiting the utility of bronchoalveolar lavage in the diagnosis of Covid-19 date: 2020-08-28 journal: Eur Respir J DOI: 10.1183/13993003.03116-2020 sha: 890d2bbb672e9546785127f3668a5d6318db2846 doc_id: 987270 cord_uid: a18lw6kf Bronchoalveolar lavage has a specific place in the diagnosis of Covid-19. The clinical performance of BAL rRt-PCR is dynamic in nature and depends on different clinical and demographic factors. report 2 and suggested a limited utility of BAL. However, the results need to be interpreted comprehensively before drawing any conclusion. In the present study, BAL was negative for SARS-CoV-2 by rRT-PCR in majority of cases that included 38 patients (48%) with strong clinical and radiological suspicion for Covid-19. This finding implies either a high false negative rate of BAL rRT-PCR or an alternate diagnosis. Hence, authors should give a detail account of the final diagnoses and treatment outcomes of the patients and correlate these with the rRT-PCR results. This will give a better picture of the clinical performance of rRT-PCR in both BAL and upper respiratory samples. Clinical test performance of rRT-PCR (in BAL/Ns/NPs) is a dynamic parameter that depends not only on its analytic sensitivity but also on the pretest probability. The pretest probability may in turn depend on the SARS-CoV-2 exposure history, disease symptoms and local disease prevalence. 3 The unexpected low positivity seen with BAL rRT-PCR in the study despite high pretest probability might be due to delayed time of sampling and/or disease stage. All these factors should have been considered while comparing the diagnostic yield in the study Bronchoalveolar lavage has a specific place in the diagnostic algorithm of Covid-19 and is usually performed in a patient with lower respiratory tract involvement and high clinical suspicion but negative Ns/NPs result. However, negative BAL results should be interpreted comprehensively in light of different clinical and demographic factors on a case-to-case basis. Limited role for bronchoalveolar lavage to exclude Covid-19 after negative upper respiratory tract swabs: a multicenter study Detection of SARS-CoV-2 in Different Types of Clinical Specimens False Negative Tests for SARS-CoV-2 Infection -Challenges and Implications