Can Fractional Exhaled Nitric Oxide with Blood Eosinophil Count Have a Place in the Diagnostic Algorithm for Asthma?

Authors

  • İlkay Koca Kalkan Department of Allergy and Clinical Immunology, University of Health Sciences, Atatürk Chest Diseases and Thoracic Surgery Training and Research Hospital, Ankara http://orcid.org/0000-0002-9788-1056
  • Gözde Köycü Buhari Department of Allergy and Clinical Immunology, University of Health Sciences, Atatürk Chest Diseases and Thoracic Surgery Training and Research Hospital, Ankara http://orcid.org/0000-0002-0787-0370
  • Hale Ateş Department of Allergy and Clinical Immunology, University of Health Sciences, Atatürk Chest Diseases and Thoracic Surgery Training and Research Hospital, Ankara http://orcid.org/0000-0001-8374-5814
  • Buket Başa Akdoğan Department of Allergy and Clinical Immunology, University of Health Sciences, Atatürk Chest Diseases and Thoracic Surgery Training and Research Hospital, Ankara http://orcid.org/0000-0003-2919-6660
  • Özlem Özdedeoğlu Department of Allergy and Clinical Immunology, University of Health Sciences, Atatürk Chest Diseases and Thoracic Surgery Training and Research Hospital, Ankara http://orcid.org/0000-0001-8421-9904
  • Kurtuluş Aksu Department of Allergy and Clinical Immunology, University of Health Sciences, Atatürk Chest Diseases and Thoracic Surgery Training and Research Hospital, Ankara http://orcid.org/0000-0001-6195-1158
  • Ferda Öner Erkekol Department of Chest Diseases, Division of Immunology and Allergy, Ankara Yıldırım Beyazıt University School of Medicine, Ankara http://orcid.org/0000-0001-9155-0304

Keywords:

Rule-out test, bronchial provocation testing, methacholine, spirometry, cut-off values

Abstract

Objective: Guidelines suggest using bronchial provocation testing (BPT), which is hard to attain, in patients with asthma-like symptoms presenting with nondiagnostic spirometric tests. To eliminate the risk of over/underdiagnosing asthma, we aimed to evaluate the predictive value of not only fractional exhaled nitric oxide (FeNO) but also other easily accessible clinical indices for ruling in/out asthma.

Materials and Methods: This retrospective study included adults presenting to our clinic with respiratory symptoms suggestive of asthma but with normal spirometric values and negative reversibility test, who underwent FeNO and methacholine BPT (MchBPT). Medical records were used to obtain descriptive characteristics, clinical history, allergy screening, eosinophils in peripheral blood, and spirometry.

Results: Among 51 patients, 19 were diagnosed with asthma. Body mass index and blood eosinophils were significantly higher in patients with positive MchBPT (p=0.042 and p=0.037, respectively). No significant difference was found in other indices, including FeNO (p=0.293). Receiver operating characteristic curve analysis revealed the best diagnostic cutoff level for FeNO as 14 ppb and blood eosinophil as 150/μl for the prediction of positive MchBPT (with 63.16%-62.5% and 80%-61% sensitivity-specificity, respectively). These two indices were the only independent predictors of positive BHR, and the model of FeNO>14ppb combined with eos>150/μl showed 100% specificity with a 100% negative predictive value.

Conclusion: Our results suggest using the combination of FeNO with blood eosinophil count as a rule-out test, adding a new step in the algorithmic diagnosis of asthma. This might avoid an unnecessary BPT procedure, reduce the risk of over/under-diagnosis of asthma, and hasten the correct diagnosis.

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Published

2021-08-20

How to Cite

1.
Koca Kalkan İlkay, Köycü Buhari G, Ateş H, Başa Akdoğan B, Özdedeoğlu Özlem, Aksu K, Öner Erkekol F. Can Fractional Exhaled Nitric Oxide with Blood Eosinophil Count Have a Place in the Diagnostic Algorithm for Asthma?. AAI [Internet]. 2021 Aug. 20 [cited 2021 Nov. 29];19(2):100-9. Available from: https://aai.org.tr/index.php/aai/article/view/643

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Section

Research Articles