The clinical utility and reliability of asbestos bodies in bronchoalveolar fluid

Although asbestos bodies are easily identified in bronchoalveolar lavage (BAL) fluid and are thought to be strongly associated with the asbestos body burden in the lung parenchyma, the clinical utility and reliability of this biologic measure of exposure has not been sufficiently studied. To assess the clinical relevance of BAL asbestos bodies we compared this bioassay of exposure to other measures of exposure and also indices of lung disease in asbestos-exposed workers (n = 71). The median concentration of asbestos bodies was 0.8 bodies per ml of BAL fluid (range 0 to 34.3). Seven workers or 9.9% had zero asbestos bodies identified in the BAL fluid. The concentration of BAL asbestos bodies was not associated with the duration of exposure (r = -0.02), the time from first exposure to asbestos (r = 0.12), or the time since last exposure to asbestos (r = 0.05). Moreover, radiographic and physiologic measures of asbestos-induced lung disease were not found to be associated with the concentration of BAL asbestos bodies. In fact, of the seven study subjects with zero BAL asbestos bodies, the mean duration of exposure was 32 yr, and six of these subjects had radiographic evidence of asbestos-induced lung disease. To assess the reliability of measuring BAL asbestos bodies, we performed a second bronchoscopy on 54 subjects and directly compared the concentration of BAL asbestos bodies from both the first and second BAL samples. Within these 54 subjects, the concentration of BAL asbestos bodies was found to be a very reliable measure (r = 0.76; p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)