From the Guidelines
Bronchoalveolar lavage (BAL) is strongly recommended in immunocompromised adults for the diagnosis and management of pulmonary conditions, particularly to exclude pulmonary infections and identify opportunistic pathogens, as it is a low-risk technique with a high diagnostic yield, as reported in a recent study published in the European Respiratory Journal in 2024 1. The procedure allows for the direct sampling of the cellular and acellular components in the distal airways and alveoli, providing valuable information for the diagnosis of conditions such as pulmonary alveolar proteinosis (PAP) and opportunistic infections.
- The usefulness of BAL for identifying the presence of PAP has been reported in several studies, with a diagnostic yield of 90.7% in one study 1.
- BAL is also crucial in excluding pulmonary infections, which can complicate PAP and account for approximately 20% of mortality, with opportunistic infections associated with a worse prognosis and higher risk of mortality 1.
- The procedure involves instilling sterile saline into a subsegmental bronchus, with a recovery of at least 30% of the instilled fluid considered adequate, and samples should be processed for comprehensive microbiological testing, including bacterial cultures, fungal stains and cultures, viral PCR panels, and specific tests for opportunistic pathogens.
- Procedural considerations include using moderate sedation, maintaining oxygen supplementation during the procedure, and monitoring for complications such as hypoxemia, bleeding, or pneumothorax, with most adverse events closely related to endoscopic technique, location, and extent of lavaged lung area, volume and temperature of instilled fluid 1.
From the Research
Recommendations for Bronchoalveolar Lavage (BAL) in Immunocompromised Adults
The following are key points to consider for BAL in immunocompromised adults:
- BAL is a useful tool in the diagnosis of pulmonary infections in immunocompromised patients 2.
- The diagnostic yield of BAL remains high in immunocompromised patients with respiratory symptoms, with an overall diagnostic yield of 34% for bacteria, 22% for CMV, 15% for P. jiroveci, 6% for other viruses, 6% for mycobacteria, and 2% for aspergillus 2.
- The pattern of opportunistic infections in immunocompromised patients diagnosed by BAL has changed over time, with significant decreases in mycobacterial infections and P. jiroveci 2.
Diagnostic Yield and Safety of BAL
- The diagnostic yield of BAL in immunocompromised patients is well established, but may vary between studies depending on the underlying disease 3.
- BAL has an acceptable tolerance in immunocompromised patients, with no significant adverse events reported in some studies 4.
- The sensitivity of BAL in pulmonary infections is 75.9%, with a specificity of 86.0%, positive predictive value of 89.6%, negative predictive value of 69.4%, and accuracy of 79.8% 5.
Role of BAL in Diagnosis and Management
- BAL remains an important tool in the diagnosis of fungal infections, such as invasive aspergillosis and pneumocystis pneumonia, and non-infectious lung diseases in immunocompromised patients 3.
- BAL can provide significant clinical benefits in selected noncritically ill patients suspected of SARS-CoV-2 infection, particularly in immunocompromised patients 4.
- A protocol for obtaining, processing, and analyzing BAL specimens can be successfully implemented in a clinical microbiology laboratory, with overall diagnostic yields of 81% for infections, 90% for hemorrhage, and 13% for neoplasms 6.