Rapid serum lidocaine determination in the coronary care unit.

Eighty-four serum lidocaine determinations were made in 33 hospitalized patients with the use of a rapid enzyme innumoassay technique. Prediction of lidocaine concentration within broad categories based on clinical assessment alone was compared with actual measurements. When serum concentrations were not considered, most episodes of lidocaine toxic reactions were obscured by associated complex clinical problems. The rapid lidocaine enzyme immunoassay is a useful tool for assisting in the detection of lidocaine toxic reactions in the coronary care unit.