Modified alkali digestion method for pulmonary asbestos fibre counts

Abstract

In using the standard alkali digestion method for pulmonary asbestos fibre count, it was found that carbonaceous particles often obscured the presence of asbestos bodies (coated fibres) rendering their quantification inaccurate, particularly in lungs with a high soot particle content and a low fibre count. We applied the chloroform-ethanol separation technique from the bleaching agent digestion method to the alkali digestion method to remove the carbonaceous particles. It was found that coated fibres are much easier to visualize and count. The uncoated fibre count was nevertheless more accurate with the original method. The coated and uncoated fibre counts from 21 lung specimens were compared using both methods. The total fibre count was considered better derived from using both techniques.