After air sampling and elution, the air sample eluate contains an unknown amount of allergens together with other materials. The proteins of interest can be quantified using immunoassays, which are sensitive, economical, and can be used for high throughput. However, the amount of antigen or allergen in an air sample may be very low and consequently the assays must be very sensitive and specific. Immunoassays use antibodies both to capture and visualize the chosen antigen. High specificity and sensitivity can best be achieved by the use of purified, characterized, and specific antibodies.