Allergy in vitro testing with ImmunoCAP gives reliable results. It has very high reproducibility and corresponds well with the clinical diagnosis by the allergy specialist. ImmunoCAP is WHO calibrated and thereby offers quantitative results which make it possible to monitor the allergy development in a patient over time. Only one blood sample is needed and it can be saved and used several times if complementary tests are requested. Allergy in vitro tests are neither affected by pharmaceutical treatment, nor by skin status (i.e. atopic dermatitis).