Diagnostic Accuracy of Liquid Biomarkers in Airway Diseases: Toward Point-of-Care Applications

Abstract

BackgroundLiquid biomarkers have shown increasing utility in the clinical management of airway diseases. Salivary and blood samples are particularly amenable to point-of-care (POC) testing due to simple specimen collection and processing. However, very few POC tests have successfully progressed to clinical application due to the uncertainty and unpredictability surrounding their diagnostic accuracy.ObjectiveTo review liquid biomarkers of airway diseases with well-established diagnostic accuracies and discuss their prospects for future POC applications.MethodologyA literature review of publications indexed in Medline or Embase was performed to evaluate the diagnostic accuracy of liquid biomarkers for chronic obstructive pulmonary disease (COPD), asthma, laryngopharyngeal reflux (LPR), and COVID-19.ResultsOf 3,628 studies, 71 fulfilled the inclusion criteria. Sputum and blood eosinophils were the most frequently investigated biomarkers for the management of asthma and COPD. Salivary pepsin was the only biomarker with a well-documented accuracy for the diagnosis of LPR. Inflammatory blood biomarkers (e.g., CRP, D-dimers, ferritin) were found to be useful to predict the severity, complications, and mortality related to COVID-19 infection.ConclusionMultiple liquid biomarkers have well-established diagnostic accuracies and are thus amenable to POC testing in clinical settings.

Patient‐centered digital biomarkers for allergic respiratory diseases and asthma: The ARIA‐EAACI approach – ARIA‐EAACI Task Force Report

“…Biomarkers for patients with asthma are urgently needed 4,5 . Some exist in specialist care (e.g., FeNO 6 or sputum eosinophils 7 ), but, to date, there are no biologic or omics biomarkers that can be largely used in primary care 8,9 . Blood eosinophils and serum total IgE are related to the treatment with anti‐IL‐5 or anti‐IgE biologics.…”

“…4,5 Some exist in specialist care (e.g., FeNO 6 or sputum eosinophils 7 ), but, to date, there are no biologic or omics biomarkers that can be largely used in primary care. 8,9 Blood eosinophils and serum total IgE are related to the treatment with anti-IL-5 or anti-IgE biologics. There are no validated biomarkers in rhinitis 10 or allergen immunotherapy (AIT).…”

Severe Acute Bronchial Asthma with Sepsis: Determining the Status of Biomarkers in the Diagnosis of the Disease

“…FeNO [ 22 ], EOS [ 23 ], and NLR [ 24 ] are efficient, feasible, consistent, and non-invasive inflammatory biomarkers. Even so, elements like smoking and prescribed medicines impact all of them [ 25 , 26 , 27 , 28 ].…”

The Emerging Clinical Significance of the Red Cell Distribution Width as a Biomarker in Chronic Obstructive Pulmonary Disease: A Systematic Review

“…However, they have stimulated the search for novel biomarkers that may complement the clinical information currently gathered from physical examination, lung function tests, and imaging procedures [ 3 ]. The established role of infection, inflammation, and immunity in the pathophysiology and the clinical progression of COPD has led to the identification of a number of biomarkers within these pathways, e.g., eosinophils, procalcitonin, neutrophil elastase, and serum amyloid A, which can be characterised from different biological matrices, blood, saliva, or sputum [ 3 , 4 , 5 , 6 ]. Though some of these biomarkers, e.g., eosinophils and procalcitonin, appear particularly promising to enhance clinical and therapeutic decisions in patients with stable COPD and AECOPD [ 7 ], the availability of additional biomarkers from routine laboratory tests might also further improve patient care in those settings that have limited access to expensive and complex analytical facilities.…”