Standardizing Nasal Fluid Processing for Respiratory Biomarker Analysis: A Comparative Study of Homogenization and Storage Methods

BackgroundNasal fluid is a valuable medium for biomarker analysis in respiratory diseases due to its accessibility and proximity to relevant pathophysiological processes. However, its heterogeneous nature presents challenges for consistent biomarker detection and quantification. This study aimed to improve protein biomarker recovery and reliability by evaluating different homogenization and storage methods for nasal fluid samples. MethodsMechanical disruption techniques using syringes and commercial BioMasher units were compared for their effectiveness in analyte recovery, and the impact of pre- and post-processing of cryogenically stored nasal samples was assessed. Inflammatory protein biomarkers relevant to respiratory diseases, including interleukin (IL)-13, IL-8/ CXCL8, myeloperoxidase (MPO), CCL11/ eotaxin-1, CCL26/ eotaxin-3, elastase, myxovirus resistance protein 1 (MxA), CCL17/ TARC, CXCL10/ IP-10), and serum amyloid A (SAA), were successfully detected in the processed nasal fluid by ELISA and Luminex assays. ResultsSignificant differences in analyte recovery were observed between homogenization methods, with greater titers of IL-5 and eotaxin-1 measured in samples processed by the syringing method. However, homogenization could be performed either before or after long-term cryogenic storage without significantly affecting protein concentrations. Spike and recovery experiments were also conducted and differences in SAA protein recovery were detected, suggesting that the matrix effects in nasal fluid can affect cytokine recovery, but variations in recovery were not significant for other biomarkers tested. ConclusionsThese findings demonstrate the potential of nasal fluid as a readily accessible medium with substantial potential to aid diagnosis and monitoring of respiratory diseases. However, given the significant impact homogenization protocols had on analyte recovery, the growing use of nasal fluid as a biospecimen in the respiratory field highlights the critical need for standardized protocol to ensure accuracy and reproducibility in future analyses.