Biological Standardization of Lolium Perenne Allergen Extract

"This is an open, unblinded and non randomized biological as proposed by the Nordic Guidelines.~Four concentrations of Lolium perenne allergen extract, together with a positive and negative control, using 10 mg/ml histamine dihydrochloride solution and a glycerinated phenol saline solution, respectively, will be tested in every patient in duplicate on the volar surface of the forearm. This test will be referred to as the Titrated Skin Prick test."