Quantitation of barbiturates by a modification of the EMIT-tox serum barbiturate assay

A modification of the Syva EMIT-tox Serum Barbiturate Assay was developed to provide a rapid and practical method for quantitating serum barbiturates. Standard curves for eight selected barbiturates were run using specific sets of standards for each. Correlation coefficients, slopes, and y-intercepts for the curves of best fit were determined by the least-squares method. Between-run and within-run precision analysis indicated acceptable reproducibility for barbiturate concentrations in high therapeutic to toxic serum levels. A case report describing the use of this method for the determination of serum pentobarbital concentrations during therapy for intracranial hypertension is presented. The modified EMIT assay may be useful for monitoring barbiturate blood levels in overdose, and when used for therapy of ischemic brain damage.