Introduction: Benign prostatic hyperplasia (BPH) and prostate carcinoma are prevalent prostatic diseases among aging males, presenting commonly with lower urinary tract symptoms (LUTS). Serum prostate-specific antigen (PSA), although widely used, lacks specificity due to elevation in benign conditions. PSA density (PSAD), defined as the ratio of total PSA to prostate volume, has emerged as a potential tool to improve diagnostic accuracy in differentiating BPH from prostate carcinoma. Aims and Objectives: To evaluate the diagnostic value of PSA density in predicting carcinoma of the prostate. Specific objectives were to measure PSAD in patients with LUTS and analyze its association with histopathological outcomes. Materials and Methods: This prospective observational study included 100 men aged ≥50 years with LUTS due to suspected prostatic disease at a tertiary center in Sarojini Naidu Medical College, Agra, UP, India over a period of one year. All patients underwent digital rectal examination, PSA testing, and ultrasound to measure prostate volume. PSAD was calculated, and diagnosis was confirmed through biopsy or histopathology following surgery. A PSAD cutoff of 0.15 ng/ml² was assessed for diagnostic performance using SPSS v26. Results: Among 100 patients, 70 were diagnosed with BPH and 30 with carcinoma prostate. PSAD ≥0.15 ng/ml² showed a sensitivity of 93.1%, specificity of 92.6%, PPV of 81.8%, NPV of 94.9%, and diagnostic accuracy of 92.7%. ROC analysis yielded an AUC of 0.929, indicating excellent discriminative ability. Conclusion: PSAD is a reliable, non-invasive tool that improves prostate cancer detection, particularly in the PSA “gray zone,” enhancing clinical decision-making and reducing unnecessary biopsies.

Prostatic neoplasms, prostate-specific antigen, prostatic hyperplasia, roc curve, biopsy, ultrasonography