Most risk-stratification instruments that have been developed to predict outcome after myocardial infarction do not make use of laboratory parameters, although several laboratory parameters have been shown to be predictors of adverse outcome. To assess the prognostic value of routine admission laboratory tests, we studied a sample of 264 of 3,746 patients with myocardial infarction from a coronary care unit database of 12,043 patients for differences between survivors and nonsurvivors at 30 days. In multivariate analyses, higher white blood cell count, higher levels of serum creatinine, glucose, and lactate dehydrogenase, and lower platelet count were identified as independent risk factors for 30-day mortality. The model that incorporated these risk factors (added laboratory parameters model) had a 17% higher predictive power than did the model that contained only conventional risk factors (conventional risk factor model). The added laboratory parameters model showed better discriminative ability than the conventional risk factor model according to the area under the curve (0.87 vs 0.80). In conclusion, routine admission laboratory tests hold significant prognostic information, with value in addition to conventional risk factors. Incorporating these tests in risk-stratification instruments will further improve risk assessment of patients with myocardial infarction.