In general, the kinetics of iBK formation under the three types of stimulation provide a fully quantitative and rich source of information relative to other methods proposed to study the kallikrein–kinin system in HAE patients, such as the consumption of high molecular weight kininogen with detection of cleavage products that may be based on immunoblotting, a semi-quantitative approach. This evidence concerns the gene KLK4 and hereditary angioedema.