INTRODUCTION AND OBJECTIVE: We performed this study to investigate the diagnostic performance of PSAD and the optimal cutoff of PSAD in a multicenter cohort of Chinese Prostate Cancer Consortium. METHODS: A total of 5220 outpatients with a PSA greater than 4.0 ng ml-1 regardless of DRE results or a PSA less than 4.0 ng ml-1 but abnormal DRE results were included from 18 large referral hospitals in China. The diagnostic performance of PSAD and the optimal cutoff were evaluated. RESULTS: A total of 5220 people patients were included in the study and 2014 (38.6%) of them were diagnosed with PCa. In patients with PSA from 4.0 to 10.0 ng ml-1, PSAD was associated with PCa and HGPCa in both univariate (OR=45.15 and p< 0.01, OR=25.38 and p< 0.01, respectively) and multivariate analysis (OR= 52.55 and p< 0.01, OR= 26.05 and p< 0.01, respectively). The AUCs of PSAD in predicting PCa and HGPCa in men with PSA 4.0-10.0 ng ml-1 were 0.627 and 0.630, respectively. With the PSAD threshold of 0.10, nearly all (89.9%) of HGPCa could be detected and avoid the biopsies in 19.5% of patients (346/1776 cases). Among these patients avoided biopsies, only 27 cases were with HGPCa. CONCLUSIONS: The diagnostic performance of PSAD was higher than PSA in all PSA ranges. In patients with PSA from 4.0-10.0 ng ml-1. We recommend 0.10 as the cutoff value of PSAD, which will get a sensitivity of nearly 90% for both PCa and HGPCa. The results of this study should be validated in prospective population-based multicenter studies.Source of Funding: This study is supported by the Fund for National Natural Science Foundation Youth Project (No. 81702514, to RC)