Bedside Lung Ultrasound for Diagnosing COVID-19 Pneumonia in the ED

lung ultrasonography
lung ultrasonography
A Danish study compared the accuracy of 3 common lung ultrasound protocols for diagnosing COVID-19 pneumonia in the emergency department.

The use of bedside lung ultrasound (LUS) can help in the identification of COVID-19 pneumonia in the emergency department (ED), according to results of a multicenter, prospective, observational study published in BMJ Open.

The study, conducted at the EDs in 3 academic hospitals in The Netherlands between March 19 and May 4, 2020, compared the accuracy of 3 commonly used LUS protocols for diagnosing COVID-19 pneumonia in the ED. Researchers used 2 reference standards for COVID-19: a positive reverse transcription polymerase chain reaction (PCR) test, and the decision of a multidisciplinary team of experts following exclusion for alternative diagnoses and blinded with respect to LUS results.

A total of 202 adult patients with suspected COVID-19 were included in the study. All participants received a regular medical workup, including history, physical examination, routine laboratory tests, and a bedside LUS in the ED. Researchers then compared 3 LUS protocols (the 6-points protocol, 8-point protocol, and 12-zone protocol) with the SARS-CoV-2 PCR test.

Results of the comparisons with the PCR with respect to sensitivity, specificity, negative predictive value, and negative likelihood ratio, were as follows:

  • 12-zone LUS: 91.4% (95% CI, 84.4-96.0), 83.5% (95% CI, 74.6-90.3), 90.0% (95% CI, 82.7-94.4), and 0.1 (95% CI, 0.05-0.2), respectively;
  • 6-points protocol: 89.9% (95% CI, 81.7-95.3), 57.5% (95% CI, 47.9-66.8), 87.8% (95% CI, 79.2-93.2), and 0.2 (95% CI, 0.1-0.3), respectively; and
  • 8-points protocol: 79.7% (95% CI, 69.9-87.6), 69.0% (95% CI, 59.6-77.4), 81.3% (95% CI, 73.8-87.0), and 0.3 (95% CI, 0.2-0.5), respectively.

When diagnostic measures were compared with the final diagnosis by the medical expert panel, 96 of the patients with a final diagnosis of COVID-19 had a positive

12-zone LUS.  The interobserver reliability of 12-zone LUS was excellent, with an intraclass correlation coefficient of 0.88 (95% CI, 0.77-0.95). There were 6 patients with false-negative results in the 12-zone LUS, and thus also in the 6-points and 8-points protocols.

The findings from the current study show that although the more efficient 6-points protocol is an excellent screening tool, the 12-zone protocol is more specific and provides a general impression on lung involvement. The investigators concluded that additional research conducted in other settings is warranted, in order to validate the current findings.


Kok B, Schuit F, Lieveld A, Azijli K, Nanayakkara PW, Bosch F. Comparing lung ultrasound: extensive versus short in COVID-19 (CLUES): a multicentre, observational study at the emergency department. BMJ Open. 2021;11(9):e048795. doi:10.1136/bmjopen-2021-048795