CTAB: Clear to Auscultation Bilaterally
CTAB is a medical abbreviation that stands for "Clear to Auscultation Bilaterally," indicating that when listening to both lungs with a stethoscope, normal breath sounds are heard without any abnormal findings such as wheezes, crackles, or diminished air movement.
What This Means Clinically
When a clinician documents "CTAB" in a physical examination, they are indicating:
- Normal breath sounds are present in both the right and left lung fields
- No adventitious sounds (abnormal sounds) are detected, including:
- No crackles (rales)
- No wheezes
- No rhonchi
- No stridor
- No pleural friction rub
- Bilateral air entry is adequate and symmetric
- No areas of diminished or absent breath sounds
Context of Use
CTAB is routinely documented during respiratory system examination as part of the physical assessment 1. Auscultation assesses airflow through the trachea-bronchial tree and helps distinguish normal respiratory sounds from abnormal ones to make correct diagnoses 1.
Important Clinical Caveat
Auscultation has significant limitations and should not be relied upon as the sole assessment method in certain clinical scenarios. In pediatric patients, bilateral breath sounds on auscultation does not rule out endobronchial intubation—studies show that 11.8% of children had right mainstem bronchus intubation despite bilateral breath sounds being confirmed 2. This limitation may be related to the Murphy eye on endotracheal tubes, which reduces the reliability of chest auscultation in detecting malpositioned tubes 2.
Documentation Standard
CTAB serves as shorthand in medical documentation to efficiently communicate that the lung examination is normal, allowing clinicians to quickly identify when respiratory pathology is absent versus when abnormal findings require further investigation or intervention.