Quantitation of bronchoalveolar lavage with methylene blue

Abstract

Bronchoalveolar lavage yields a return that is composed of lung liquid and lavage liquid in variable and unknown proportions. Concentrations of chemicals and cells in lung liquid have been presented by previous workers in relative terms, sometimes relating them to the albumin content on the assumption that it is comparatively stable. We report here the use of methylene blue in the introduced fluid as an external marker. This allows the dilution, and thus absolute values, to be calculated. We found the concentrations of albumin in lung fluid to be significantly higher in a group of patients with sarcoidosis (0.50 mg/ml +/- 0.40, mean +/- standard deviation) than in a control group (0.15 mg/ml +/- 0.07; p less than 0.02). Absolute cell counts of lymphocytes in lung fluid lavaged from patients with sarcoidosis were higher than those for control patients (154 lymphocytes/ml +/- 98.9 versus 4 +/- 2.6). There was a correlation between the absolute number of lymphocytes and the albumin concentration per milliliter lung liquid (r = 0.71, p less than 0.001).