This prospective, multicenter study obtained peripheral blood samples for gene expression score (GES) before MPI in 537 consecutive patients Patients with abnormal MPI usually underwent invasive coronary angiography; all others had research coronary computed tomographic angiography, with core laboratories defining coronary anatomy A total of 431 patients completed GES, coronary imaging (invasive coronary angiography or computed tomographic angiography), and MPI Mean age was 56±10 years (48% women) The prespecified primary end point was GES receiver-operating characteristics analysis to discriminate ≥50% stenosis (15% prevalence by core laboratory analysis) Area under the receiver-operating characteristics curve for GES was 0 79 (95% confidence interval, 0 73-0 84; P<0 001), with sensitivity, specificity, and negative predictive value of 89%, 52%, and 96%, respectively, at a prespecified threshold of ≤15 with 46% of patients below this score The GES outperformed clinical factors by receiver-operating characteristics and reclassification analysis and showed significant correlation with maximum percent stenosis. Six-month follow-up on 97% of patients showed that 27 of 28 patients with adverse cardiovascular events or revascularization had GES >15 Site and core-laboratory MPI had areas under the curve of 0 59 and 0 63, respectively, significantly less than GES.