Interobserver Variability in Analysis of Asbestos Fibres and Asbestos Bodies in Human Lung Tissue

Abstract

Two different methods of quantifying asbestos fibre burden were assessed and the counts obtained were compared with semi-quantitative asbestos body counts in corresponding tissue sections. Comparison of the two methods found significantly different asbestos fibre counts between specimens. Each technique showed wide limits of agreement for reproducibility and interobserver variability as assessed by Bland-Altman plots, such that a repeated count could not necessarily be expected to lie within the same exposure category. Asbestos body counts in tissue sections were reproducible with good correlation between observers. Asbestos body and asbestos fibre counts showed correlation in some samples but not others. Counting of asbestos bodies is a valuable screening technique as the finding of asbestos bodies is accepted as a marker of significant asbestos exposure. When no asbestos bodies are identified asbestos fibres estimations may be useful in proving asbestos exposure. Different techniques are not interchangeable and each laboratory should establish a background range from unexposed individuals.

Reproducibility of asbestos body counts in digestions of autopsy and surgical lung tissue

“…Since most of the individuals studied have not been occupationally exposed to asbestos, further studies are needed in order to know if the results obtained are applicable to more highly exposed individuals. Our literature review retrieved two articles evaluating the reproducibility of lung AB counting in individuals who had been exposed to asbestos [Roberts et al, 2004;Wright et al, 2008]. Roberts et al reported an interobserver kappa index of 0.60, although the semiquantitative method used to measure AB (none, few, and many) is probably less accurate than the method described in the present study.…”

Focused X-Ray Histological Analyses to Reveal Asbestos Fibers and Bodies in Lungs and Pleura of Asbestos-Exposed Subjects

“…Compared with conventional techniques, synchrotron methods are valuable tools to detect and characterize asbestos fibers and bodies in histological tissues from exposed patients, and provide links to tissue response and pathological changes. Most important, we believe that XRF analyses with Ca and Fe detection promises great efficiency in evaluating the real asbestos body burden of lung tissues of exposed subjects, thus competing with current well-accepted techniques like light microscopy (Roberts et al, 2004).…”

“…Asbestos fiber burden can be evaluated using various methods, all requiring extraction from the lung and concentration of both coated and uncoated asbestos fibers. The techniques are well validated, but today there is little inter-laboratory standardization, particularly in the expression of results (Roggli & Pratt, 1983;Roggli, 1990;Roberts et al, 2004). The limit of asbestos fiber counts is that only small regions of tissue can be monitored and the digestive procedures used may alter asbestos coating and thus the percentages of coated and uncoated fibers.…”

“…Asbestos body count alone is considered a good estimation of exposure, proportional to total asbestos burden of the lung (Roberts et al, 2004). Thus it could be obtained from microscopy investigations of histological tissues.…”