Correlation of the "EMIT" urine barbiturate assay with a spectrophotometric serum barbiturate assay in suspected overdose.

A rapid method for determining the presence of barbiturate in serum has been needed for some time. Presently used methods are all relatively time-consuming. A rapid immunoassay for the detection of barbiturate in urine, the “Enzyme Multiplied Immunoassay Technique” (EMIT), has recently become available. We have compared results of the EMIT urine assay with results of a spectrophotometric assay of serum (203 patients). Our purpose was: (a) to determine whether a negative result would be obtained with the EMIT assay in cases in which barbiturate was not a factor in coma, and (b) to determine whether a positive EMIT result would be obtained when a significant (3 mg/liter) quantity of barbiturate was in fact present in the serum. We conclude that the EMIT urine assay suffices to indicate clinically if barbiturate may be responsible if a patient is comatose. Results for a specimen (i.e., positive or negative) can be obtained in 5-10 mm, so time saved by using the EMIT urine assay as a screening technique is significant.