Accuracy, precision, and interferences of three modified EMIT procedures for determining serum phenobarbital, urine morphine, and urine cocaine metabolite with a Cobas-Fara

Abstract

Abstract Sung and Neely‘s proposed cost-reductive EMITTM (Syva Co., Palo Alto, CA) procedure allowed a 20-fold increase in the number of tests that can be performed with a single EMIT kit (1). They extensively diluted both EMIT reagents and supplemented the reaction medium with more substrate (glucose 6-phosphate, G6P) and cofactor (NAD+) to saturate the enzyme activity. This principle has been successfully applied to the determination of serum theophylline (1), serum anticonvulsanta (2), urineopiates (3), and urine benzoylecgonine, a cocaine metabolite (4).