The authors describe the method of the nasal challenge test for assessment of acetylsalicylic acid (ASA) intolerance. This test was made in 50 patients with nasal polyps without anamnestic records of ASA intolerance, incl. 23 who had nasal polyps associated with bronchial asthma. The test was made also in 10 healthy controls. In all patients for two weeks before the test all treatment of rhinosinusitis was discontinued, treatment of bronchial asthma proceeded, The challenging agent was a freshly prepared solution of acetylsalicylic lysine, Aspegic (Synthéla- bo). The total dose during the challenge test was 9 mg lysine (corresponds to 5 mg acetylsalicylic acid) administered bilaterally. As placebo saline was administered. For administration a dispenser from Syntaris spray was used. During the test the nasal patency was evaluated by anterior active rhinomanometry. The basic objectively assessed parameter was the nasal flow in ml/s bilaterally at a pressure difference of 75 Pa. The patients recorded subjective sensations of nasal patency, nasal secretion and the feeling of dyspnoea on a ten-centimeter visual scale. The measurements were taken 25 and 50 minutes after administration acetylsalicylic lysine (lys- ASA). The test was evaluated as positive if after unilateral administration of lys-ASA a 40% decline of the nasal patency occurred and this drop was associated with a subjective change of nasal patency, nasal secretion of lacrimation. The test was evaluated as positive if bilateral drop of nasal patency by 40% or more occurred even if subjective changes were absent. The test was evaluated as negative, if no drop occurred on either side by 40 % or more. The test was evaluated as negative if a drop by 40 % of more occurred after placebo, when after administration of lys-ASA no further drop greater than 40 % occurred. The test was evaluated as negative if the flow value did not decline even when the patient reported subjectively perceived increased nasal secretion after administration of lys-ASA. The test could not be evaluated in two patients where already during the first measurements the nasal patency was very restricted, and in another six patients because of increased nasal sensitivity where after administration of placebo a drop by 40% or more occurred at least on one side and after administration of lys-ASA a further drop by 40% or more. In the control group of 10 volunteers the test was always negative. The change after placebo was in all smaller than 40 %. None of the patients developed bronchoconstriction, no drop of FEV1 or subjective despnoea were recorded.

        Key words: nasal challenge test, lysine aspirin, aspirin intolerance, nasal polyps.