Lung Ultrasound Scan Findings Can Help Identify False-Negative COVID-19 Test Results

A new study has found that the integration of lung ultrasound (LUS) with clinical evaluation is associated with increased sensitivity for the diagnosis of COVID-19 pneumonia, and may facilitate the identification of false negative SARS-CoV-2 RT-PCR results.

Accurate diagnostic testing to identify SARS-CoV-2 infection is critical. Although highly specific, SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR), has shown, in clinical practice, to be affected by a non-insignificant proportion of false negative results. For the study, the researchers enrolled consecutive adult patients with symptoms potentially related to SARS-CoV-2 infection admitted to the emergency department (ED) of an Italian academic hospital. Immediately after the initial assessment, a LUS evaluation was performed and the likelihood SARS-CoV-2 infection, based on both clinical and LUS findings (integrated assessment), was recorded. RT-PCR SARS-CoV-2 detection was subsequently performed.

The study enrolled 228 patients; 107 patients (46.9%) had SARS-CoV-2 infection. Sensitivity and negative predictive value of the clinical-LUS integrated assessment were higher than first RT-PCR [94.4% (95% CI 88.2-97.9), vs. 80.4% (95% CI 71.6-87.4); 95% (95% CI 89.5-98.2), vs. 85.2% (95% CI 78.3-90.6)]. Among the 142 patients who initially had negative RT-PCR, 21 resulted positive at a subsequent molecular test performed within 72 hours. All these false negative cases were correctly identified by the integrated assessment.

Based on the findings, the researchers have suggested that, in patients presenting to the ED with symptoms commonly associated with SARS-CoV-2 infection, the integration of LUS with clinical evaluation has high sensitivity and specificity for COVID-19 pneumonia and it may help to identify false negative results occurring with RT-PCR.