ObjectivesTo evaluate the usefulness of a novel qualitative, rapid, bedside immunoassay device for the detection of elevated creatine kinase MBmass(CK-MB) and myoglobin as a supportive tool for decision-making by the physician who is evaluating patients who present with chest pain.DesignProspective study.SettingPrehospital (mobile intensive care units).PatientsThree hundred twenty-eight consecutive patients, age 71 +/- 13 yrs (64% males), who were admitted to the hospital via Shahal's mobile intensive care units.InterventionDuring a 6-month period, based on clinical presentations and electrocardiograms, the mobile's physicians classified patients into groups of high or low probability of having an acute myocardial infarction and, thereafter, used a rapid bedside STATus kit[registered sign] (Spectral Diagnostics, Toronto, Ontario, Canada) to determine blood creatine kinase/MB and myoglobin.Measurements and Main Results2 hrs after onset, diagnostic sensitivities, specificities, and positive and negative predictive values for physicians were as follows: 71%, 90%, 46%, and 96%, respectively, compared with 100%, 85%, 44%, and 100%, respectively, if assessed by the kit.ConclusionsIf used 2 to 12 hrs from the onset of symptoms, this device is a convenient diagnostic aid to prevent a misdiagnosis of acute myocardial infarction or unnecessary hospitalization to exclude infarction. This tool may be a promising cost-cutting factor in these days of escalating expenses and dwindling resources. (Crit Care Med 1999; 27:1085-1089)