Research & Development

PExA’s strategy for research is to co-operate with leading international research groups and carry on the work performed over the past few years in identifying biomarkers for various lung diseases.

In parallel with this work, PExA is running a development project to further develop, streamline and simplify the PExA method to collect particles from the small airways.

Publications involving PExA’s method

Kokelj S, Östling J, Fromell K, Vanfleteren LEGW, Olsson HK, Nilsson Ekdahl K, Nilsson B, Olin AC. Activation of the Complement and Coagulation Systems in the Small Airways in Asthma. Respiration. 2023 Jul 7:1-11
Hirdman, G., Bodén, E., Kjellström, S. et al. Proteomic characteristics and diagnostic potential of exhaled breath particles in patients with COVID-19. Clin Proteom 20, 13, 2023
Broberg, E., Pierre, L., Fakhro, M. et al. Releasing high positive end-expiratory pressure to a low level generates a pronounced increase in particle flow from the airways. ICMx 11, 12, 2023
Emilsson, Ö.I., Kokelj, S., Östling, J. et al. Exhaled biomarkers in adults with non-productive cough. Respir Res 24, 65, 2023
Andreasson, J., Bodén, E., Fakhro, M. et al. Exhaled phospholipid transfer protein and hepatocyte growth factor receptor in lung adenocarcinomaRespir Res 23, 369, 2022
Lindstedt, S., and Hyllen, S. New insight: particle flow rate from the airways as an indicator of cardiac failure in the intensive care unit. ESC Heart Failure, 2022
Ljungkvist G, Tinnerberg H, Löndahl J, Klang T, Viklund E, Kim JL, Schiöler L, Forsgard N, Olin AC. Exploring a new method for the assessment of metal exposure by analysis of exhaled breath of welders. Int Arch Occup Environ Health. 2022 Aug;95(6):1255-1265
Östling, J., Van Geest, M., Olsson, H.K. et al. A novel non-invasive method allowing for discovery of pathologically relevant proteins from small airways. Clin Proteom 19, 20, 2022
Holz O, et al. Inflammatory cytokines can be monitored in exhaled breath particles following segmental and inhalation endotoxin challenge in healthy volunteers, Scientific Report, 2022
Koca H, et al. Surfactant protein A in particles in exhaled air and plasma, Respiratory Physiology & Neurobiology, 2022
Viklund E, et al. Severe acute respiratory syndrome coronavirus 2 can be detected in exhaled aerosol sampled during a few minutes of breathing or coughing, Influeza and other respiratory viruses, 2022
Kokelj S, et al. Smoking induces sex-specific changes in the small airway proteome, Respiratory Research, 2021
Hallgren F, et al. Particle flow rate from the airways as fingerprint diagnostics in mechanical ventilation in the intensive care unit: a randomised controlled study, ERJ Open Reserach, 2021
Stenlo M, et al. Monitoring lung injury with particle flow rate in LPS- and COVID-19-induced ARDS, Physiological Reports, 2021
Viklund E, et al. Current smoking alters phospholipid- and surfactant protein A levels in small airway lining fluid: An explorative study on exhaled breath, PLoS One, 2021
Hussain-Alkhateeb L, et al. Novel non-invasive particles in exhaled air method to explore the lining fluid of small airways--a European population-based cohort study, Open Respiratory Research, 2021
Rosenkilde Laursen K, et al. An RCT of acute health effects in COPD-patients after passive vape exposure from e-cigarettes, European Clinical Respiratory Journal, 2020
Greening N, et al. Small droplet emission in exhaled breath during different breathing manoeuvres:Implications for clinical lung function testing during COVID‐19,Allergy: European Journal of Allergy & Clinical Immunology, 2020
Broberg E, et al. Mechanically ventilated patients exhibit decreased particle flow in exhaled breath as compared to normal breathing patients, ERJ Open Resarch, 2020
Kokelj S, et al. Intra-individual variation of particles in exhaled air and of the contents of Surfactant protein A and albumin, PLOS ONE, 2020
Stenlo M, et al. Increased particle flow rate from airways precedes clinical signs of ARDS in a porcine model of LPS-induced acute lung injury, American Journal of Physiology, 2020
Broberg E, et al. Particle Flow Profiles From the Airways Measured by PExA Differ in Lung Transplant Recipients Who Develop Primary Graft Dysfunction, Experimental and Clinical Transplanlantion, 2019
Carpaij O, Assessing small airways dysfunction in asthma, asthma remission and healthy controls using particles in exhaled air, ERJ Open Research, 2019
Behndig A L, et al. Surfactant Protein A in particles in exhaled air (PExA), bronchial lavage and bronchial wash - a methodological comparison Respiratory Research, 2019
Broberg E, et al. Different particle flow patterns from the airways after recruitment manoeuvres using volume-controlled or pressure-controlled ventilation Intensive Care Medicine Experimental, 2019
Bake B, et al. Exhaled particles and small airways Respiratory Research, 2019
Soares M, et al. Particles in exhaled air (PExA): non-invasive phenotyping of small airways disease in adult asthma Journal of Breath research, 2018
Broberg E, et al. A new way of monitoring mechanical ventilation by measurement of particle flow from the Airways using Pexa method in vivo and during ex vivo lung perfusion in DCD lung transplantation Intensive Care Medicine Experimental, 2018
Ljungkvist G, et al. Two techniques to sample non-volatiles in breath—exemplified by methadone Journal of Breath Research, 2017
Larsson P, et al. The effect of exhalation flow on endogenous particle emission and phospholipid composition. Respiratory Physiology & Neurobiology, 2017
Horváth I, et al. A European Respiratory Society technical standard: exhaled biomarkers in lung disease. European Respiratory Journal, 2017
Bake B, et al. Exhaled Particles After a Standardized Breathing Maneuver. J Aerosol Med Pulm Drug Deliv. 2017
Ericson P, et al. Low levels of exhaled surfactant protein A associated with BOS after lung transplantation. Transplantation Direct 2016
Emilsson ÖI, et al. Respiratory symptoms, sleep-disordered breathing and biomarkers in nocturnal gastroesophageal reflux. Respir Res. 2016.
Beck O, et al. Potential of Mass Spectrometry in Developing Clinical Laboratory Biomarkers of Nonvolatiles in Exhaled Breath. Clin Chem. 2016;62(1):84-91.
Larsson P, et al. Exhaled particles as markers of small airway inflammation in subjects with asthma. Clin Physiol Funct Imaging, 2015
Lärstad M, et al. Surfactant protein A in exhaled endogenous particles is decreased in chronic obstructive pulmonary disease (COPD) patients: a pilot study. PLoS One 2015 Dec
Bredberg A, et al. Analysis of manganese and iron in exhaled endogenous particles. J Analyt Antomic Spect 2014:29:730 -735
Olin AC. Particles in Exhaled Air—A novel method of sampling of-non-volatiles in exhaled air. In Volatile Biomarkers. Editor Amann A.
Emilsson OI, et al. Biomarkers for gastroesophageal reflux in respiratory diseases. Gastroenterol Res Pract. 2013;2013:148086.
Bredberg A, et al. Comparison of exhaled endogenous particles from smokers and non-smokers using multivariate analysis. Respiration. 2013;86(2):135-42.
Holmgren H, et al. Effects of breath holding at low and high lung volumes on amount of exhaled particles. Respir Physiol Neurobiol. 2013;185:228-34.
Olin AC. Induced sputum, exhaled nitric oxide, and particles in exhaled air in assessing airways inflammation in occupational exposures. Clin Chest Med. 2012;33:771-82.
Bredberg A, et al. Exhaled endogenous particles contain lung proteins. Clin Chem 2012; 58:431-40.
Almstrand AC, et al. TOF-SIMS analysis of exhaled particles from patients with asthma and healthy controls. Eur Respir J 2012;39:59-66.
Larsson L, et al. Surfactant protein A and albumin in particles in exhaled air. Respir Med 2012; 106:197-204
Holmgren H, et al. Relation between humidity and size of exhaled particles. Aerosol Med Pulm Drug Deliv 2011;24:254-60
Holmgren H, et al. Size distribution of exhaled particles in the range from 0.01 to 2.0 μm. Journal ofAerosol Science 2010;41:439-446
Almstrand AC, et al. Effect of Airway Opening on Production of Exhaled Particles. J Appl Physiol 2010;108:584-8
Almstrand AC, et al. Airway monitoring by collection and mass spectrometric analysis of exhaled particles. Anal Chem. 2009; 81:662-8.

PExA 2.0

PExA 2.0 has been developed on the basis of the instrument developed at the Sahlgrenska Academy in nine specimens (PExA 1.0) and...



Suitable standard methods that can be used for analysis include ELISA, MS, LC and HPLC. As a service to those customers who...



For each sampling, disposable items are required such as substrate surfaces and nozzles. These components...