ASBESTOS CONTENT OF BRONCHOALVEOLAR LAVAGE FLUID - A COMPARISON OF LIGHT AND SCANNING ELECTRON-MICROSCOPIC ANALYSIS

We studied the asbestos content of bronchoalveolar lavage fluid (BALF) from 4 patients with asbestosis, 17 asbestos exposed but without asbe stosis, 15 with idiopathic pulmonary fibrosis (IPF) and 9 nonexposed v olunteers. The cellular lavage pellet was digested and filtered for as bestos body (AB) quantification by light microscopy (LM) and analysis of numbers and types of uncoated fibers (UF) by scanning electron micr oscopy (SEM) and energy dispersive x-ray analysis. BALF of asbestosis patients had significantly higher AB content than that of the combined II)F and volunteer groups. The UF content as determined by SEM was si milar in all four groups. Commercial amphiboles (amosite or crocidolit e) were identified more frequently in BALF from patients with asbestos is than from the other groups. ABs were detected by SEM only in highly exposed individuals. We conclude that the findings of > 1 AB per 10(6 ) cells or 1 AB/mL BALF by LM and of ABs or commercial amphibole fiber s by SEM are indicative of considerable exposure to asbestos in the ma jority of cases.