Quantification of a major bovine allergen by a two‐site immunometric assay based on monoclonal antibodies

A two-site immunometric assay based on monoclonal antibodies (mAb) was developed for the measurement of a 20-kDa major allergen of cow. The sensitivity of this assay was (BDA20) 1 ng/ml. It was used to measure airborne allergen concentrations in 10 Finnish cowsheds. The mean concentration of the BDA20 measured at two stationary sites was 280 ng/m3. Concentrations varied more than 10-fold among cowsheds (54-804 ng/m3). The mean intertest coefficient of variation was 8.2%, and the mean intratest variation 4.1%.