Assessment of B-lines in Lung Ultrasound: Thresholds and Interpretation
What is confirmed by the source
According to the EFSUMB position paper on POCUS in primary care (Andersen et al., 2026), the basic competencies of a physician include the ability to describe the localization and nature of pleural and lung changes, including focal B-lines / comet tail artifacts as manifestations of interstitial syndrome.
The same materials include the following as assessed signs: thickened and/or fragmented pleura, consolidations, air and fluid bronchogram, as well as signs of pneumothorax — absence of lung sliding, absence of lung pulse, lung point, and barcode sign.
Thresholds for counting B-lines
The provided fragments of the source lack numerical thresholds (e.g., the number of B-lines per intercostal space or total count by zones), as well as definitions of a 'positive' interstitial syndrome. Specific quantitative criteria and their source — [clarify].
| Parameter | Data from fragments |
|---|---|
| B-lines as a sign of interstitial syndrome | Confirmed (EFSUMB, Andersen et al., 2026) |
| Threshold for the number of B-lines per intercostal space | [clarify] — absent in fragments |
| Zone-based counting protocols | [clarify] — absent in fragments |
| Associated signs (pleura, consolidations, bronchogram) | Confirmed as objects of description (EFSUMB) |
Practical conclusion
Based on the available materials, B-lines should be described qualitatively within the structure of pleura and lung parenchyma assessment according to EFSUMB POCUS competencies. To formulate quantitative thresholds and counting protocols, a specialized source on lung ultrasound is required, which is absent in the provided fragments — [clarify].
Frequently asked questions
Is there a numerical threshold for the number of B-lines in the source?
No. The provided fragments do not contain numerical thresholds for counting B-lines — [clarify].
How does the source define the role of B-lines?
According to EFSUMB (Andersen et al., 2026), focal B-lines / comet tail artifacts are described as manifestations of interstitial syndrome.
What other lung signs should be described?
Thickened/fragmented pleura, consolidations, air and fluid bronchogram, as well as signs of pneumothorax (absence of lung sliding, lung pulse, lung point, barcode sign).
Are zone-based protocols for counting B-lines specified?
No, zone-based protocols are not provided in the fragments — [clarify].