We quantified between-method differences in estimated PSA-DT at PSA relapse after RP and evaluated how these differences affect discrimination of prostate cancer (PCa) death.<h4>Methods</h4>Men who underwent RP in 2007-2024 and subsequently developed a PSA relapse, defined as two consecutive values above 0.2 ng/ml, were included. The gene discussed is KLK3; the disease is prostate carcinoma.