A simplified radioenzymatic method for the study of whole blood histamine release in patients receiving radiographic contrast media.

With the availability of a newly developed, histamine-dependent allergy blood test, the authors studied the effect of ionic and nonionic radiocontrast media (RCM) on the in vitro release of histamine from whole blood obtained from 61 patients undergoing diagnostic arteriography. The ionic RCM, sodium meglumine diatrizoate (60 to 378 mmol/L), induced the release of a significantly (P less than .005) higher amount of histamine from blood compared with the nonionic agents, iopamidol and ioversol. Diatrizoate triggered significantly (P less than .05) more histamine release from the blood of eight patients with a history of adverse reactions to RCM than it did in 53 nonreactors; however, there was no appreciable difference in histamine release between reactive and nonreactive groups when stimulated with iopamidol and ioversol.