Bronchoalveolar lavage procedure
Bronchoalveolar lavage (BAL) was performed in patients in cases of suspected respiratory infection to determine the offending microbe, suspected pulmonary hemosiderosis, aspiration pneumonia, pulmonary alveolar proteinosis and unclear diagnosis. All BAL samples were collected and analysed in accordance with the recommended standard procedure of ATS/ERS guideline 2,3. BAL fluid samples with greater than 25 neutrophils and lower than 10 epithelial cells per microscopic field are considered to be relatively free of contamination. 10⁴ colony forming units per millilitre of BAL fluid are considered to indicate established bacterial infection 2. BAL fluid results, which did not meet these criterions, were excluded.