Demonstration of asbestos fibers in a ten-year-old sputum sample

Our plain-English summary of Demonstration of asbestos fibers in a ten-year-old sputum sample, by D.S. Heller, R.E. Gordon (American Journal of Industrial Medicine, 1991).

The study

• Authors: D.S. Heller, R.E. Gordon
• Journal: American Journal of Industrial Medicine
• Published: 1991;20(3):415-9
• Type of article: Case report, Letter
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This letter to the editor described a single case. A 44-year-old man was diagnosed with poorly differentiated large cell carcinoma of the right upper lobe of the lung, with mediastinal spread, and died shortly afterward. From 1959 to 1963 he had worked as a machinist in a shipyard, a potential occupational asbestos exposure. He had smoked one pack of cigarettes a day from age 16 to 34. No lung tissue was available. About a week before his death, his wife saved paper towels holding material he had coughed up. They were opened ten years later. The authors scraped 0.01 grams (dry weight) of material from them, much of it towel fibers. Light microscopy found no asbestos bodies. Electron microscopy found 3,782,500 chrysotile and amosite fibers per gram dry weight, in a 1 to 1 ratio, with a detection limit of 1,891,250. The authors judged this to be above background. They compared it with their laboratory's values for lung tissue from unexposed people, noting that they were unaware of any standard reference number for sputum and that sputum is not the ideal sample. They concluded that electron microscopy of digested material is reliable and very sensitive.

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: case report (letter to the editor) describing one patient
• Who was studied: One 44-year-old man with poorly differentiated large cell carcinoma of the right upper lobe with mediastinal metastases. He died about ten years before the analysis. The sample was dried sputum on paper towels saved by his widow; no lung tissue was available.
• Exposure: Potential occupational asbestos exposure from 1959 to 1963 while working as a machinist in a shipyard. He was later a school teacher. He also smoked one pack of cigarettes per day from age 16 to 34.
• Main results:
  • Light microscopy of the sputum preparation found no asbestos bodies.
  • Transmission electron microscopy found 3,782,500 chrysotile and amphibole asbestos fibers per gram dry weight of the scraped material, with a limit of detection of 1,891,250.
  • Energy-dispersive spectroscopy confirmed chrysotile and identified the amphibole as amosite. The two were present in a 1 to 1 ratio.
  • The authors compared the count with their laboratory's reference values for lung tissue from nonexposed people at autopsy. These were 0 to 50,000 per gram wet weight for chrysotile (mean 20,000) and 0 to 5,000 per gram wet weight for amphiboles (mean 1,000). They judged the sputum finding to be above background.
• The authors' conclusion: The authors concluded that electron microscopic examination of digested material is reliable and very sensitive for detecting and quantifying asbestos, even in tiny samples such as sputum. They considered it probable that lung tissue, had it been available, would have shown an even larger fiber burden.
• Limitations the authors state:
  • Sputum is not the ideal sample for detecting asbestos.
  • The amount of material was extremely small (0.01 grams dry weight), and much of its weight was paper towel fibers.
  • The authors were unaware of any standard reference number for asbestos fibers in sputum. They compared the result with lung-tissue reference values instead.

Topics

Medical terms in this study, explained in our Lexicon: Sputum.

Related studies

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• Assessment of hazardous dust exposure by BAL and induced sputum — E. Fireman, J. Greif, et al. (1999)
• Perls' Prussian Blue Stains of Lung Tissue, Bronchoalveolar Lavage, and Sputum — A.J. Ghio, V.L. Roggli (2021)
• Can semi-automated image cytometry on induced sputum become a screening tool for lung cancer? Evaluation of quantitative semi-automated sputum cytometry on radon- and uranium-exposed workers — W. Marek, N. Kotschy-Lang, et al. (2001)
• Asbestos bodies in the sputum of asbestos workers: correlation with occupational exposure — C. Paris, F. Galateau-Salle, et al. (2002)

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