What is Bronchoalveolar Lavage (BAL)?
Bronchoalveolar lavage (BAL) is performed during flexible bronchoscopy. A small amount of sterile saline is instilled into a selected part of the lung and gently suctioned back. The fluid is sent for tests for infection (including tuberculosis and fungi), cell counts and cancer cells.
Why it is done
- Suspected TB when sputum is negative or cannot be produced
- Pneumonia that is not improving or in people with weakened immunity
- Evaluation of interstitial lung disease
- Suspected lung cancer
Before the procedure
- Fasting for about 6 hours before the procedure (you will be given exact instructions)
- Inform the team about blood thinners, diabetes medicines and allergies — some medicines may need to be paused
- Blood tests and recent imaging (CT scan) are usually reviewed beforehand
- Bring a family member or friend to accompany you home
During the procedure
- The bronchoscope is wedged gently into the target airway
- Sterile saline is instilled in small portions and suctioned back
- You may feel the urge to cough briefly
After the procedure
- You will be observed for a short period until the sedation wears off
- Avoid eating or drinking for about 1–2 hours, until the throat numbness settles
- A mild sore throat, cough or slight blood-streaked sputum may occur briefly
- Do not drive or operate machinery for the rest of the day after sedation
- Biopsy results usually take a few days; your follow-up will be scheduled
Safety & risks
Bronchoscopy is generally a safe procedure. Possible risks include sore throat, transient fever, minor bleeding, low oxygen levels during the procedure and, rarely, pneumothorax (especially after lung biopsy). Your doctor will discuss the risks relevant to you before obtaining consent.
Preparation instructions may differ for individual patients — please follow the specific advice given at your consultation.