It is challenging to define a specific PSA value below which prostate cancer can be definitively ruled out. Even at very low PSA levels, such as below 1 ng/ml, prostate cancer can be detected in approximately 6.6% of patients. Conversely, as PSA levels rise, the likelihood of detecting prostate cancer increases. For instance, when PSA levels range between 3.1 and 4 ng/ml, prostate cancer is observed in 26.9% of patients.