Diagnostic value of asbestos bodies in bronchoalveolar lavage fluid

Our plain-English summary of Diagnostic value of asbestos bodies in bronchoalveolar lavage fluid, by P. De Vuyst, P. Dumortier, E. Moulin, et al (The American Review of Respiratory Disease, 1987).

The study

• Authors: P. De Vuyst, P. Dumortier, E. Moulin, N. Yourassowsky, J.C. Yernault
• Journal: The American Review of Respiratory Disease
• Published: 1987;136(5):1219-24
• Cited by: 69 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004945).

Abstract

Asbestos bodies (AB) were counted by light microscopy in bronchoalveolar lavage (BAL) fluid obtained from 563 subjects. The presence of AB was found to reflect occupational exposure to asbestos and was rarely found in unexposed control subjects at concentrations above 1/ml of fluid (6.9% of white collar workers and 17.8% of blue collar workers). The overlap of results observed between subjects with definite exposure and those without underlines the difficulty in assessing exposure by questioning alone, which leads to underestimations or even overestimations of the risk. The highest counts (log mean, 120.5 AB/ml; range, 0 to 42,600) were found in patients with radiologic evidence of asbestosis, most likely reflecting the known association of this disease with retention of large amounts of long amphiboles, rather than in patients with pleural disease. A considerable overlap of results was also observed between groups with different diseases or without any apparent disease. Apart from uncertainties in the radiologic diagnosis, this may be explained by differences in latency since first exposure, in individual response to asbestos inhalation, or in pathogenic properties of different asbestos types. Because the presence of AB in BAL fluid appears to be a marker of exposure and not of disease, AB are more likely to be detected in patients presenting with asbestos-related diseases but in whom exposure is not confirmed by the occupational history (65 of 78 cases).

In plain English

The authors counted asbestos bodies (asbestos fibers coated with an iron-protein layer) under a light microscope. The bodies came from bronchoalveolar lavage, a lung washing, of 563 people at a Brussels hospital between January 1980 and June 1986. Based on interviews, 215 people had definite occupational asbestos exposure, 116 had probable exposure and 232 had no known occupational exposure (117 blue collar and 115 white collar workers). Asbestos bodies were found in 96.8% of the definite, 84.5% of the probable, 52.2% of the blue collar and 25.3% of the white collar group. The average count was 120.5 per ml (a log mean, averaged on a logarithmic scale) in patients with X-ray signs of asbestosis, against 4.77 per ml in benign pleural disease and 3.57 per ml in exposed people with neither asbestos-suggestive X-ray changes nor respiratory cancer; results overlapped widely. In 78 patients with lesions compatible with asbestos whose exposure routine questioning had not established, the lavage was positive in 65. The authors concluded that asbestos bodies in lavage fluid were a good marker of exposure but not of disease. They noted lost sensitivity at low counts and that fiber types were not identified.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Series of patients referred for bronchoalveolar lavage, with asbestos body counts compared across exposure groups and disease groups
• Who was studied: 563 subjects whose lavage fluid was examined between January 1980 and June 1986 at the Chest Department, Erasme Hospital, Brussels, Belgium. 215 had definite exposure and 116 had probable exposure. 232 had no direct or indirect known occupational exposure (117 blue collar and 115 white collar workers). The subjects included patients with asbestosis, pleural lesions, mesothelioma (38 pleural, 2 peritoneal) or lung cancer, exposed people without apparent disease, and people without known exposure who had other lung diseases.
• Exposure: Occupational asbestos exposure, classified as definite, probable or none known. Physicians took a medical and occupational history and did not use a standardized questionnaire. Definite-exposure jobs included insulation, asbestos-cement, heating mechanic, stove-building and brake-lining factory work. Fiber type was generally not analyzed. Five brake lining factory workers without apparent disease were exposed only to chrysotile.
• Main results:
  • Definite exposure group (215): asbestos bodies were found in the lavage fluid of 96.8%.
  • All patients with more than 1,000 asbestos bodies per ml, and 36 of the 37 with more than 100 per ml, were in the definite exposure group.
  • Probable exposure group (116): 84.5% had asbestos bodies in the lavage fluid, and 53.5% had more than 1 per ml.
  • Blue collar workers without known occupational exposure (117): asbestos bodies were detected in 52.2%, and 17.8% had more than 1 per ml.
  • White collar workers without known occupational exposure (115): asbestos bodies were detected in 25.3%, and 6.9% had more than 1 per ml.
  • In control subjects (blue plus white collar) whose lavage contained asbestos bodies, counts were usually low: less than 5 per ml in 94.4% and less than 10 per ml in 98.8% of the positive control subjects.
  • Lavage fluid was positive for asbestos bodies in 98.3% of patients with asbestosis, 95% of those with benign pleural disease, and 75% of those with malignant mesothelioma.
  • The authors describe the 120.5 asbestos bodies per ml in patients with radiologic evidence of asbestosis as a log mean. Individual counts in that group ranged from 0 to 42,600 per ml.
  • The mean count was 120.5 per ml in patients with asbestosis. This compared with 4.77 per ml in those with benign pleural disease (p less than 0.001). It also compared with 3.57 per ml in Category 5, the 82 definitely or probably exposed subjects with neither chest X-ray abnormalities suggestive of asbestos-related lesions nor respiratory malignancy (p less than 0.001). Results overlapped widely between groups.
  • The mean count was 7.6 per ml in patients with malignant mesothelioma (15.2 for the definite exposure group only). It was 8.5 per ml in those with bronchial carcinoma (19.1 for the definite exposure group only).
  • Fifteen of 40 patients with mesothelioma (37.5%) had less than 1 asbestos body per ml of lavage fluid.
  • Some patients had ill-defined exposure but lesions compatible with an asbestos cause. In 65 of 78 such cases, a positive lavage confirmed or revealed exposure that routine questioning had not established.
  • Among positive results in the definite exposure group, asbestos body counts were weakly negatively correlated with time since the end of exposure (r = -0.238, p less than 0.01).
• The authors' conclusion: The authors concluded that asbestos bodies in lavage fluid are a good marker of exposure but not a good marker of disease. They judged the test most useful in patients whose X-rays suggest asbestos-related disease but whose exposure history is unclear.
• Limitations the authors state:
  • The authors noted a loss of sensitivity at low concentrations (below 1 asbestos body per ml). At these levels, repeated counts disagreed in 16% of patients and repeated lavages in 20%.
  • The technique did not identify which fiber type the asbestos bodies formed on, or the fiber sizes.
  • The authors describe very short chrysotile fibers as the bulk of asbestos fibers in the general population. These fibers do not form asbestos bodies, so this light-microscopy method does not detect them.
  • Exposure was assessed by questioning without a standardized questionnaire. The authors considered the difficulty of assessing exposure by questioning alone to be one cause of the overlap between groups.
  • Some negative results may be false negatives caused by poor fluid recovery. Examples were severe air-flow limitation and compression of the lung by mesothelioma.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Bronchoalveolar Lavage (BAL), Occupational Exposure, Amphibole Group, Latency, BAL Fluid, Occupational History.

Related studies

• Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers — P. Dumortier, P. De Vuyst, et al. (1990)
• Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey — P. Dumortier, L. Coplü, et al. (2001)
• Asbestos bodies in bronchoalveolar lavage fluid in relation to occupational history — A. Karjalainen, S. Anttila, et al. (1994)
• Fibres and asbestos bodies in bronchoalveolar lavage fluids of asbestos sprayers — T. Tuomi, P. Oksa, et al. (1992)
• Pleural plaques, asbestos exposure, and asbestos bodies in bronchoalveolar lavage fluid — E. Orlowski, J.C. Pairon, et al. (1994)
• Inorganic particles in bronchoalveolar lavage fluids from nonoccupationally exposed subjects — M. Falchi, L. Biondo, et al. (1996)

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