Brightling CE. Clinical applications of induced sputum. Chest. 2006;129:1344-8.
Bacci E, Cianchetti S, Bartoli M, Dente FL, Di Franco A, Vagaggini B, et al. Low sputum eosinophils predict the lack of response to beclomethasone in symptomatic asthmatic patients. Chest. 2006;129:565-72.
Korevaar DA, Westerhof GA, Wang J, Cohen JF, Spijker R, Sterk PJ, et al. Diagnostic accuracy of minimally invasive markers for detection of airway eosinophilia in asthma: a systematic review and meta-analysis. Lancet Respir Med. 2015;3:290-300.
Westerhof GA, Korevaar DA, Amelink M, de Nijs SB, de Groot JC, Wang J, et al. Biomarkers to identify sputum eosinophilia in different adult asthma phenotypes. Eur Respir J. 2015;46:688-96.
Schleich FN, Seidel L, Sele J, Manise M, Quaedvlieg V, Michils A, et al. Exhaled nitric oxide thresholds associated with a sputum eosinophil count ≥3% in a cohort of unselected patients with asthma. Thorax. 2010;65:1039-44.
Wagener AH, de Nijs SB, Lutter R, Sousa AR, Weersink EJM, Bel EH, et al. External validation of blood eosinophils, FE(NO) and serum periostin as surrogates for sputum eosinophils in asthma. Thorax. 2015;70:115-20.
Taylor DR. Using biomarkers in the assessment of airways disease. J Allergy Clin Immunol. 2011;128:927-34. quiz 935-936
Demarche SF, Schleich FN, Paulus VA, Henket MA, Van Hees TJ, Louis RE. Asthma Control and Sputum Eosinophils: A Longitudinal Study in Daily Practice. J Allergy Clin Immunol Pract. 2017. http://dx.doi.org/10.1016/j.jaip.2017.01.026.
Louis R, Godinas L, Schleich F. Induced sputum - towards normal values. In: Loukides S, Kostikas K, Barnes PJ, editors. Non invasive assessment of airways inflammation in asthma and COPD. Athens: Paschalidis Medical Publications; 2011. p. 113-23.
Hastie AT, Moore WC, Li H, Rector BM, Ortega VE, Pascual RM, et al. Biomarker surrogates do not accurately predict sputum eosinophil and neutrophil percentages in asthmatic subjects. J Allergy Clin Immunol. 2013;132:72-80.e12.
Coumou H, Bel EH. Improving the diagnosis of eosinophilic asthma. Expert Rev Respir Med. 2016;10:1093-103.
Justice AC, Covinsky KE, Berlin JA. Assessing the generalizability of prognostic information. Ann Intern Med. 1999;130:515-24.
Szefler SJ, Wenzel S, Brown R, Erzurum SC, Fahy JV, Hamilton RG, et al. Asthma outcomes: biomarkers. J Allergy Clin Immunol. 2012;129:S9-23.