The Value of Lung Ultrasound to Detect the Early Pleural and Pulmonary Pathologies in Nonhospitalized COVID‐19‐Suspected Cases in a Population With a Low Prevalence of COVID‐19 Infection: A Prospective Study in 297 Subjects

OBJECTIVES: This prospective study aimed to evaluate the value of B‐mode lung ultrasound (LUS) for the early diagnosis of coronavirus disease 2019 (COVID‐19) infection in nonhospitalized COVID‐19 suspected cases in a population with a low prevalence of disease. METHODS: From April 2020 to June 2020, in an ambulatory testing center for COVID‐19‐suspected cases, 297 subjects were examined by LUS before a nasopharyngeal swab was taken for a reverse transcription polymerase chain reaction (RT‐PCR) test. The following LUS findings were defined as pathological ultrasound findings and were analyzed: the presence of 1) pleural effusion, 2) B‐lines, 3) fragmented visceral pleura, 4) consolidation, and 5) air bronchogram in the consolidation. The LUS findings were compared with the RT‐PCR test results. RESULTS: The result of the RT‐PCR test for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) was positive in 11 and negative in 286 subjects, and the prevalence of COVID‐19 infection in the study participants was 3.7%. On LUS, a pathological finding could be detected in 56/297 (18.9%) study participants. The LUS revealed a sensitivity of 27.3%, a specificity of 81.5%, a positive predictive value of 5.4%, a negative predictive value of 96.7%, and a diagnostic accuracy of 79.9% for the identification of COVID‐19 infection. CONCLUSIONS: For the identification of COVID‐19 infection, LUS is highly sensitive to the patient spectrum and to the prevalence of the disease. Due to the low diagnostic performance in nonhospitalized COVID‐19 cases in low‐prevalence areas, LUS cannot be considered to be an adequate method for making a diagnosis in this group.