To evaluate the supplemental value of serial troponin I (Trp) measurements when combined with a clinical model composed of six clinical parameters in predicting in-hospital adverse event rates, a total of 118 consecutive patients admitted over a 23-month period with intermediate- or high-risk unstable angina or non-Q wave myocardial infarction (MI) as defined by AHCPR criteria who had coronary angiography within 72 hours of hospitalization were studied. Presenting clinical characteristics were graded using a previously validated variation of the Braunwald criteria (RUSH model). The RUSH model clinical score includes six clinical parameters: age, diabetes, intravenous nitroglycerin, pre-admission calcium-channel and beta-blocker, ST depression and post-MI angina (< 2 weeks), and creates an estimated probability of MI or death. The RUSH model was compared to serial Trp levels drawn at 6-hour intervals (0, 6 and 12 hours). An abnormal Trp value was defined as > 2.0 mg/dl. Outcome measures included death, MI, recurrent chest pain and new ST or T changes and enzyme elevation. One death, 23 MIs and 24 other adverse clinical events occurred. The event group had a RUSH score predictive of 12.7 12.4% risk and the no-event group had a score of 13.2 10.2% risk (p = 0.64). The Trp positive group had a clinical score predicting 14.2 13.2% risk and the Trp negative group had a score of 11.7 9.3% risk (p = 0.21). Patients with elevated Trp had an adverse event rate of 32/50 (64%) vs. 21/68 (31%) in patients with normal Trp (p < 0.0004). Elevated Trp had 60.4% sensitivity and 72.3% specificity, odds ratio of 3.97 (1.71 9.33), as well as 64% positive and 69.1% negative predictive values for predicting adverse events. Thus, there was significant incremental value to adding Trp to the clinical score when predicting outcomes in patients with intermediate- and high-risk clinical scores. When Trp was abnormal, it was useful when predicting higher risk; if Trp was normal, it was useful predicting lower but still elevated risk. Consequently, in a population selected for intermediate and high risk, the presence or absence of elevated Trp I is a sensitive and specific additive predictor to clinical score to predict need for revascularization and adverse in-hospital outcomes, as suggested in current guidelines.