You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is 58 year-old man present with complain of urinary frequency, hesitancy, or dysuria. A digital rectal examination confirms the presence of a firm, hard, asymmetrical and stony prostate. . As next investigation, PSA levels test was done. All are true about PSA except? and explain in detail?
Serum PSA parameters : It is sensitive but not specific Serum PSA -normal : <4ng/ml PSA density : serum PSA / volume PSA volume : PSA velocity of 0.75 ng/mL per year measured at least 3 times over a period of 1.5 to 2 yrs is significant to diagnose Prostate cancer. Free form : for BPH Bound form : for cancer Upper-age-specific reference value of serum PSA : Age Upper age-specific PSA(ng/mL) 40-49 yrs 2.5 50-59 yrs 3.5 60-69 yrs 4.5 70-79 yrs 6.5 PSA is a product of prostatic epithelium and is normally secreted in the semen.