Objective To study the value of serum troponin I(cTnI)in risk stratification of elderly patients with unstable angina pectoris(UAP).Methods Serum cTnI levels were measured in 22 healthy subjects(control group),27 stable angina peetoris(SAP)and 72 UAP elderly patients,respectively.Cardiac events(non fatal myocardial infarction,cardiac sudden death)were observed within 1 month of hospitalization.Serum cTnI≥1.5 μg/L was considered as the cutoff level for myocardial damage.Results Serum cTnI levels in the UAP group were higher than those in the SAP and control group [(1.96±0.61)μg/L,(0.68±0.19)μg/L and(0.46±0.10)μg/L,respectively](P＜0.01).In the UAP group,serum cTnI levels increased with increase of Braunwald classification class[(1.25±0.38)μg/L,(2.12±0.34)μg/L and(3.06±0.72)μg/L,respectively](P＜0.05).In Braunwald class Ⅲ patients,the rate of cardiac events in patients with serum cTnI≥1.5 μg/L was much higher than that in those with cTnI＜1.5μg/L(16.7%vs 6.3%,P＜0.05),risk ratio 2.05(95%confidence limit 1.02-9.78).The positive predictive value of serum cTnI≥1.5μg/L for cardiac events was 44.3%and the negative predictive value was 84.8%.Conclusions Detection of serum cTnI has clinical value in risk stratification of elderly atients with UAP.