A method and device for rapidly, non-invasively and inexpensively differentiating between allergic rhinitis, upper respiratory tract viral infection and bacterial sinusitis, comprising a support strip upon which is fixed discrete indicators of pH, protein content, nitrite content, leukocyte esterase activity, and eosinophil content or other measure of a substance found in allergic secretions, such as TAME esterase, of a sample with which said reagent test strip is contacted. Contact of a nasal secretion with the device of this invention permits differentiation between allergic, bacterial and viral conditions, based on pH, protein content, leukocyte esterase activity, nitrite content, eosinophil content and TAME esterase activity. The invention further provides a novel means for collecting nasal secretions to facilitate differential diagnosis of sinusitis, upper respiratory tract viral infection and allergic rhinitis.