Comparison of Two Methods of Processing Induced Sputum: Selected versus Entire Sputum
- 1 February 1998
- journal article
- research article
- Published by American Thoracic Society in American Journal of Respiratory and Critical Care Medicine
- Vol. 157 (2), 665-668
- https://doi.org/10.1164/ajrccm.157.2.9705095
Abstract
Sputum analysis is increasingly used to assess airway inflammation in asthma. The analysis of sputum is currently performed with two techniques, i.e., analysis of selected sputum (plugs) and analysis of entire sputum. To investigate the diagnostic value of these two methods, we compared total and differential cell counts and supernatant eosinophil cationic protein (ECP) in selected and entire sputum collected on two occasions in a group of healthy and asthmatic subjects. We induced sputum with hypertonic saline in 18 asthmatics and in eight healthy subjects. On one occasion we analyzed selected sputum, and on another occasion we analyzed entire sputum. In each sample we measured total and differential cell counts and ECP concentration in supernatant. We found a higher percentage of eosinophils (15.3 versus 8.3%; p < 0.01), more viable nonsquamous cells (80.6 versus 71.8%; p < 0.01), and higher levels of ECP (548 versus 105 microg/L; p < 0.001) in selected sputum as compared with entire sputum, whereas the percentage of neutrophils was higher in the entire sputum (42.7 versus 33.3%; p < 0.05). The percentage of eosinophils and ECP concentration were significantly and similarly increased in both selected and entire sputum of asthmatic subjects, i.e., independent of the method of sputum analysis. In conclusion, the selected sputum method may indeed provide more viable cells, more eosinophils, and a higher concentration of ECP. However, both the selected sputum and the entire sputum method have the same diagnostic value in distinguishing asthmatics from healthy subjects.Keywords
This publication has 11 references indexed in Scilit:
- Repeatability of cellular and soluble markers of inflammation in induced sputum from patients with asthmaEuropean Respiratory Journal, 1996
- Indices of airway inflammation in induced sputum: reproducibility and validity of cell and fluid-phase measurements.American Journal of Respiratory and Critical Care Medicine, 1996
- Measurement of inflammatory indices in induced sputum: effects of selection of sputum to minimize salivary contaminationEuropean Respiratory Journal, 1996
- Analysis of induced sputum to examine the effects of prednisone on airway inflammation in asthmatic subjectsJournal of Allergy and Clinical Immunology, 1994
- Non‐invasive assessment of bronchial inflammation in asthma: no correlation between eosinophilia of induced sputum and bronchial responsiveness to inhaled hypertonic salineClinical and Experimental Allergy, 1994
- The cardinal importance of sputum microscopyClinical and Experimental Allergy, 1994
- Analysis of cellular and biochemical constituents of induced sputum after allergen challenge: A method for studying allergic airway inflammationJournal of Allergy and Clinical Immunology, 1994
- Cellular and Biochemical Analysis of Induced Sputum from Asthmatic and from Healthy SubjectsAmerican Review of Respiratory Disease, 1993
- Use of induced sputum cell counts to investigate airway inflammation in asthma.Thorax, 1992
- STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENTThe Lancet, 1986