A comparison of the "EMIT" assay with two iodinated radioimmunoassays for diphenylhydantoin

In the treatment of epilepsy, it is important for the laboratory to provide blood diphenylhydantoin levels accurately and quickly. However, physicians have often obtained laboratory results which have been inconsistent with the patient's clinical condition. We examined the "Enzyme Multiplied Immuno Technique" (EMIT) and two iodinated radioimmunoassay procedures for their suitability to provide quick and accurate blood diphenylhydantoin levels in laboratories that perform relatively few assays. The results indicated that all three procedures can be used with reasonable success. We found that the simplicity and the long shelf-life of the EMIT procedure made it very desirable for institutions that have a small volume of diphenylhydantoin assays.