Citation	Primary reason for exclusion
An SH, Tian WQ, Li JY. Utility of fractional exhaled nitric oxide in children with asthma. Zhongguo Dang Dai Er Ke Za Zhi. 2015;17(8):134-7.	Not population of interest (includes children < 5 year)
Avital A, Uwyyed K, Berkman N, et al. Exhaled nitric oxide and asthma in young children. Pediatr Pulmonol. 2001 Oct;32(4):308-13.	Not population of interest (includes children < 5 year)
Backer V, Sverrild A, Porsbjerg C. FeNO and AHR mannitol in patients referred to an out-of-hospital asthma clinic: a real-life study. J Asthma. 2014 May;51(4):411-6.	No outcomes of interest
Thomas B, Chay OM, Allen JC Jr, Chiang AS, Pugalenthi A, Goh A, et al. Concordance between bronchial hyperresponsiveness, fractional exhaled nitric oxide, and asthma control in children. Pediatr Pulmonol. 2016 Oct;51(10):100-9.	No outcomes of interest
Bobolea ID, Barranco P, Lopez-Carrasco V, Calderon O, Guillen D, Quirce S. Is methacholine challenge sufficient to rule out bronchial hyperresponsiveness in patients with suspected asthma? J Allergy Clin Immunol. 2012;129(Suppl. 1):AB3.	Not FeNO
Boon M, Meyts I, Proesmans M, Vermeulen FL, Jorissen M, De Boeck K. Diagnostic accuracy of nitric oxide measurements to detect primary ciliary dyskinesia. Eur J Clin Invest. 2014 May;44(5):477-85.	Not target condition
Brannan JD, Adoni H, Daw L, Huang HC, Hurwitz M, Figurski D. Fraction exhaled NO in patients referred to pulmonary function laboratory (PFLAB) for mannitol challenge. Respirology. 2013;18:43.	Conference abstract
Brouwer A.F.J., Visser C.A.N., Duiverman E.J., Roorda R.J., Brand PLP. Is home spirometry useful in diagnosing asthma in children with nonspecific respiratory symptoms? Pediatr Pulmonol. 2010 April 2010;45(4):326-32.	Not FeNO
Ceng J, Jin XY. The diagnostic value of fractional exhaled nitricoxide test in patients with cough variant asthma. J Intern Med Concepts Prac. 2011;6:125-7.	Unable to locate
Chai J, Jiang P, Qian X. The value of exhaled nitric oxide in diagnosis of bronchial asthma. Zhong Guo Hu Xi Yu Jian Hu Za Zhi. 2010;04:81-4.	Unable to locate
Chancafe-Morgan J, Ramos-Quispe Y, Gomez-García R, Vargas-Espinal J, Puente-Maestú L. Validity of the fractional exhaled nitric oxide (FeNO) for identification of bronchial hyperresponsiveness in a pulmonary function laboratory. Eur Respir J. 2013;42(Suppl. 57):P1273.	Conference abstract
Chen. 2017.	Unable to locate
Cirillo I, Ricciardolo FL, Medusei G, et al. Exhaled nitric oxide may predict bronchial hyperreactivity in patients with allergic rhinitis. Int Arch Allergy Immunol. 2013;160: 322-8.	Not target condition
El Halawani SM, Ly NT, Mahon RT, et al. Exhaled nitric oxide as a predictor of exercise-induced bronchoconstriction. Chest. 2003;124:639-43.	Not target condition
Fang S, Chen SY, He X, Shen QX, Fan HZ, Wu XP, et al. Evaluating the efficacy of fractional exhaled nitric oxide and impulse oscillometry in screening out cough variant asthma from patients with subacute cough. Zhonghua Yi Xue Za Zhi. 2017;97:2338-43.	Not available in English
Florentin A, Acouetey DS, Remen T, et al. Exhaled nitric oxide and screening for occupational asthma in two at-risk sectors: bakery and hairdressing. Int J Tuberc Lung Dis. 2014 Jun;18(6):744-50.	Not population of interest (occupational exposure)
Franklin PJ, Turner SW, Le Souef PN, Stick SM. Exhaled nitric oxide and asthma: complex interactions between atopy, airway responsiveness, and symptoms in a community population of children. Thorax. 2003;58:1048-52.	No outcomes of interest
Giovannini M, Valli M, Ribuffo V, et al. Relationship between methacholine challenge testing and exhaled nitric oxide in adult patients with suspected bronchial asthma. Eur Ann Allergy Clin Immunol. 2014;46:109-13.	No outcomes of interest
Glowacka E, Jedynak-Wasowicz U, Sanak M, Lis G. Exhaled eicosanoid profiles in children with atopic asthma and healthy controls. Pediatr Pulmonol. 2013;48: 324-35.	Not target condition
Hahn PY, Morgenthaler TI, Lim KG. Use of exhaled nitric oxide in predicting response to inhaled corticosteroids for chronic cough. Mayo Clin Proc. 2007;82:1350-5.	No outcomes of interest
Henriksen AH, Lingaas-Holmen T, Sue-Chu M, et al. Combined use of exhaled nitric oxide and airway hyperresponsiveness in characterizing asthma in a large population survey. Eur Respir J. 2000 May;15(5):849-55.	Not FeNO alone
Hsu JY, Wang CY, Cheng YW, Chou MC. Optimal value of fractional exhaled nitric oxide in inhaled corticosteroid treatment for patients with chronic cough of unknown cause. J Chin Med Assoc. 2013;76:15-19.	No outcomes of interest
Inoue T, Akashi K, Watanabe M, Ikeda Y, Ashi-zuka S, Motoki T, et al. Periostin as a biomarker for the diagnosis of pediatric asthma. Pediatr Allergy Immunol. 2016;27:521-6.	Not FeNO
Ji XM, Wang KX, Chen JP, Zhou X, Wang DY, Zheng CH. Clinical significance of fractional exhaled nitric oxide test in children with chronic cough. China Modern Doctor. 2013;51:39-41.	Unable to locate
Jiang XB, Huang M, Yin KS, Zhu Y. Diagnostic value of fractional exhaled nitric oxide in non-typical bronchial asthma. Chin J Postgrad Med. 2012;35:17-19.	Unable to locate
Johnson B, Steenbruggen I, Graham BL, et al. Improving spirometry testing by understanding patient preferences. E RJ Open Res. 2021;7(1):712-2020.	Not FeNO
Kaplan AG. Chronic cough in adults: make the diagnosis and make a difference. Pulm Ther. 2019;5: 11-21.	Not relevant study design
Karrasch S, Linde K, Rücker G, et al. Accuracy of FeNO for diagnosing asthma: a systematic review. Thorax. 2017;72:109-16.	Systematic review, already considered
Korevaar DA, Westerhof GA, Wang J, et al. Diagnostic accuracy of minimally invasive markers for detection of airway eosinophilia in asthma: a systematic review and metaanalysis. Lancet Respir Med. 2015;3:290-300.	Systematic review, already considered
Lemiere C, D’Alpaos V, Chaboillez S, et al. Investigation of occupational asthma: sputum cell counts or exhaled nitric oxide? Chest. 2010 Mar;137(3):617-22.	Not population of interest (occupational exposure)
Lin G. The clinical diagnosis value of exhaled nitric oxide test in chronic cough. Chin Modern Med. 2013;20:42-5.	Unable to locate
Linkosalo L, Lehtimäki L, Holm K, et al. Relation of bronchial and alveolar nitric oxide to exercise-induced bronchoconstriction in atopic children and adolescents. Pediatr Allergy Immunol. 2012;23:360-6.	Not target condition
Liu N, Zhao D, Wu M. Exhaled nitric oxide measurement in diagnosis of bronchial asthma in children. Nan Jing Da Xue Bao: Zi Ran Ke Xue edition. 2011;4:553-6.	Unable to locate
Mahut B, Peiffer C, Thibaudon M, Chevalier-Bidaud B, Defrance-Hutinet MF, Trinquart L, et al. What does a single exhaled nitric oxide measurement tell us in asthmatic children? J Asthma. 2009;46: 810-4.	No outcomes of interest
Malmberg LP, Pelkonen AS, Haahtela T, Turpeinen M. Exhaled nitric oxide rather than lung function distinguishes preschool children with probable asthma. Thorax. 2003;58:494-9.	Population (children < 5 years)
Maniscalco M, Faraone S, Sofia M, Molino A, Vatrella A, Zedda A. Extended analysis of exhaled and nasal nitric oxide for the evaluation of chronic cough. Respir Med. 2015;109:970-4.	Not target condition
Martin MJ, Wilson E, Gerrard-Tarpey W, et al. The utility of exhaled nitric oxide in patients with suspected asthma. Thorax. 2016 Jun;71(6):562-4.	Letter
Mathew S, Cliff I, Agarwal S, Lim A, Allen M, Mustfa N. Relationship between exhaled nitric oxide and methacholine challenge test in suspected asthma. Am J Respir Crit Care Med. 2011;183. Available at: http://ajrccm.atsjournals.org/cgi/reprint/183/1_MeetingAbstracts/A5554?sid = 0209d9f3-c74d-409d-8e6e-81ebe76d2328.	Conference abstract
Munnik P, van der Lee I, Fijn J, et al. Comparison of FeNO and histamine hyperresponsiveness in diagnosing asthma in new referrals. Respir Med. 2010 Jun;104(6):801-7.	No outcomes of interest
Nayak, UB, Morakhia NV, Scharya VK, Srinivas L. A study of fraction of exhaled nitric oxide levels as a diagnostic marker in patients with bronchial asthma. Journal, Indian Academy of Clinical Medicine. 2013;14(2):123-7.	Unable to locate
Ni J, Cheng Q, Feng Y, Cao B, Cheng L, Wan H. Exhaled nitric oxide combined with relevant factors in the diagnosis of cough variant asthma. J Diagn Concepts Pract. 2014;13:606-9.	Unable to locate
Oh MJ, Lee JY, Lee BJ, Choi DC. Exhaled nitric oxide measurement is useful for the exclusion of nonasthmatic eosinophilic bronchitis in patients with chronic cough. Chest. 2008;134:990-5.	Not target condition
Pérez Tarazona S, Martínez Camacho RM, Alfonso Diego J, Escolano Serrano S, Talens Gandía J. Diagnostic value of exhaled nitric oxide measurement in mild asthma. An Pediatr (Barc). 2011;75(5):320-8.	Not available in English
Pizzimenti S, Heffler E, Piccioni P, Bugiani M, Migliore E, Guida G, et al. Usefulness of exhaled nitric oxide (FeNO) measured by a portable analyzer to diagnose cough variant asthma in a clinical setting of chronic cough. Allergy. 2009;64:395.	Conference abstract
Prieto L, Ferrer A, Ponce S, Palop J, Marin J. Exhaled nitric oxide measurement is not useful for predicting the response to inhaled corticosteroids in subjects with chronic cough. Chest. 2009;136:816-22.	No outcomes of interest
Qiu JP, Jin XY, Shen HY. Application of fractional exhaled nitric oxide and impulse oscillometry in patients with chronic cough. Int J Respir. 2012;32:1297-300.	Unable to locate
Raj D, Lodha R, Mukherjee A, Sethi T, Agrawal A, Kabra SK. Fractional exhaled nitric oxide in children with acute exacerbation of asthma. Indian Pediatr. 2014 Feb;51(2):105-11.	No outcomes of interest
Ramser M, Hammer J, Amacher A, et al. The value of exhaled nitric oxide in predicting bronchial hyperresponsiveness in children. J Asthma. 2008 Apr;45(3):191-5.	No outcomes of interest
Ren XB, Liu CT, Huang YF, Zhu T. The diagnostic value of the fractional exhaled nitric oxide for asthma. Chin J Respir Crit Care Methods. 2009;8:322-6.	Unable to locate
Sastre J, Costa C, del Garcia Potro M, Aguado E, Mahillo I, Fernandez-Nieto M. Changes in exhaled nitric oxide after inhalation challenge with occupational agents. J Investig Allergol Clin Immunol. 2013; 23:421-7.	Not population of interest (occupational exposure)
Shimoda T, Obase Y, Kishikawa R, Iwanaga T, Miyatake A, Kasayama S. The fractional exhaled nitric oxide and serum high sensitivity C-reactive protein levels in cough variant asthma and typical bronchial asthma. Allergol Int. 2013;62:251-7.	No outcomes of interest
Seo Yeon Y, Yoon Hee K, Min Kwang B, Hyung Jung K, Chul Min A, Seong Han K, et al. Repeated fractional exhaled nitric oxide measurements is not essential for asthma screening. J Investig Allergol Clin Immunol. 2017.	Unable to locate
Shen X, Chen C, Zhou N, Huang J, Xiuqin Z. Feasibility study of fractional exhaled nitric oxide in the diagnosis of cough variant asthma. Int J Respir 2015; 35:329-32.	Unable to locate
Singer F, Luchsinger I, Inci D, Knauer N, Latzin P, Wildhaber JH, et al. Exhaled nitric oxide in symptomatic children at preschool age predicts later asthma. Allergy. 2013 Apr;68(4):531-8.	Not population of interest (includes children < 5 years)
Visitsunthorn N, Mahawichit N, Maneechotesuwan K. Association between levels of fractional exhaled nitric oxide and asthma exacerbations in Thai children. Respirology. 2017 Jan;22(1):71-7.	No outcomes of interest
Xu YL, Ma XT, Yang ZG. Fractional exhaled nitric oxide in the diagnosis of bronchial asthma. Henan Med Res. 2014;23:23-5.	Unable to locate
Yang YJ, Zheng XW, Yang GL. Study on the diagnostic value of fractional exhaled nitric oxide in bronchial asthma. Ningxia Med J. 2013;35:835-7.	Unable to locate
Yao HJ, Zhang RM, Li ZK. Fractional exhaled nitric oxide in diagnosis of bronchial asthma. Int J Respir. 2013;33:508-12. Abstract available at: https://www.oriprobe.com/journals/gwyx-hxxt/2013_7.html	Unable to locate full article
Ye L, Gong Y, Tong YY, Jin ML. The etiological diagnosis value of fractional exhaled nitric oxide test in patients with chronic cough. J Clin Intern Med 2010;27:601-602.	Unable to locate
Yi F, Chen R, Luo W, Xu D, Han L, Liu B, et al. Validity of fractional exhaled nitric oxide in diagnosis of corticosteroid-responsive cough. Chest. 2016;149:1042-51.	Not target condition
Zetterquist W, Marteus H, Hedlin G, Alving K. Increased exhaled nitrite in children with allergic asthma is not related to nitric oxide formation. Clin Respir J. 2008;2:166-74.	No outcomes of interest
Zhang YM, Lin JT, Su N, et al. Values of fractional exhaled nitric oxide in the diagnosis of chronic cough. Chung Hua I Hsueh Tsa Chih. 2011;91:1254-8.	Not available in English
Zhu H, Yu X, Hao C, Wang Y, Yang X, Lu Y, et al. The diagnostic value of the fractional exhaled nitric oxide for cough variant asthma in children. Zhonghua Jie He Hu Xi Za Zhi. 38(5):352-5.	Not available in English
Zhu N, He J, Chen XD. Diagnostic value of fractional exhaled nitric oxide in the diagnosis of cough variant asthma. J Clin Pulm Med. 2014;19:1628-31.	Not available in English