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Updated: Aug 9, 2026

Methodology for Sputum Induction and Laboratory Processing
Published on: December 17, 2017
Comparison of cell fixation methods of induced sputum specimens: an immunocytochemical analysis
Julie St-Laurent1, Marie-Eve Boulay, Philippe Prince
1Unité de recherche en pneumologie, Centre de recherche de l'Hôpital Laval, Institut universitaire de cardiologie et de pneumologie, Québec, Québec, Canada.
Abstract:
Induced sputum (IS) is a non-invasive method to evaluate airway inflammation. Various techniques are used to fix IS cells but their respective value has never been compared. We aimed to determine the best IS cell fixation technique for cellular markers staining. Cells were fixed using four methods: 1) periodate-paraformaldehyde-lysine (PLP)-sucrose, 2) paraformaldehyde 4% on slide and 3) in solution and 4) acetone-methanol. Analysis was based on percentage of positive cells compared to total cell counts stained by hematoxylin and quality of staining. Using PLP-sucrose resulted in a higher percentage of positive cells for CD3 and a better quality of staining. Acetone-methanol showed a lower percentage of positive cells for CD68 and a poor quality. PLP-sucrose gives the best results for the preservation of the studied cell markers and acetone-methanol the worst.
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