Prick tests in the diagnosis of anaphylaxis to general anaesthetics

Pre-charged prick tests and intradermal skin tests (two dilutions) were tested simultaneously in 79 patients using seven drugs (suxamethonium, gallamine, alcuronium, pancuronium, vecuronium, fentanyl and thiopentone) commonly administered during general anaesthesia. Fifty-seven of the patients had suffered anaphylaxis to anaesthetics: 50 had been tested previously (19.5 +/- 13.5 months) by intradermal tests (group 1) and seven were tested for the first time (group 2). Six patients had suffered a side effect during anaesthesia which was unrelated to anaesthetic agents (group 3) and 16 were control subjects (group 4). Prick and intradermal skin tests were simultaneously positive in 98 instances out of 553 (17.7%) and negative in 440 out of 553 (79.6%)--a correlation of 538 out of 553 (97.3%; P less than 0.001). In groups 1, 2 and 3 the correlation was 426 out of 441 (96.6%; P less than 0.001). In group 1, a correlation was observed between the diameters of the weals (r = 0.5; P less than 0.001) obtained by prick and intradermal skin tests, and between the diameters of the flares (r = 0.5; P less than 0.001).