KLK3 and prostate carcinoma: <h4>Objective</h4>This study aimed to develop and validate a nomogram model integrating routinely available parameters, making it applicable to primary healthcare settings for optimizing prostate cancer (PCa) risk stratification in patients with elevated prostate-specific antigen (PSA) levels, aiming to reduce unnecessary biopsies.<h4>Methods</h4>This study included a retrospective cohort of 2, 844 patients who underwent prostate biopsy (885 malignant and 1, 959 benign cases), who were randomly allocated to a training set and an internal validation set in a 7:3 ratio.