Aim Airway mucins are promising biomarkers in respiratory diseases. In this study, we aimed to identify a suitable sputum collection and processing method, as well as qualify a bioanalytical method for soluble MUC5AC and MUC5B quantification in clinical samples.

Method Mucins were quantified in induced and spontaneous sputum collected from the same COPD patients and following various sample processing procedures. Our LC-MS/MS method used truncated recombinant mucins as surrogate analytes and a surrogate matrix approach.

Results Frozen spontaneous sputum was found to be a suitable and convenient matrix for mucin quantification and fit-for-purpose method qualification was performed.

Conclusion Our methodology provides accurate and reliable MUC5AC and MUC5B quantification and facilitates multi-site clinical studies in COPD and potentially other respiratory diseases.

W.S., S.M., C.H., A.K., I.C.S., M.G., H.K., J.H.L., K.C., A.I.R. are or were employees of AstraZeneca at the time this work was conducted and may hold stock ownership and/or stock options or interests in the company. D.V., W.W., A.W., K.S., M.Y., W.R.M. performed work while employed by PPD, a part of Thermo Fisher Scientific. The authors employment and stock investments do not affect the authenticity and objectivity of the experimental results detailed in this manuscript.

AstraZeneca provided funding to PPD for the conduct of this study

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