PSA is a single-chain glycoprotein that has chymotrypsinlike properties. The upper limit of normal for PSA is 4 ng/mL. Some advocate age-related cutoffs, such as 2.5 ng/mL for the fifth decade of life, 3.5 ng/mL for the sixth decade of life, and 4.5 ng/mL for the seventh decade of life. Others advocate race-specific reference ranges. It is the region of the prostate gland that grows throughout life and causes the disease of benign prostatic enlargement. [7] [8] This area, not always considered a zone, [5] is usually devoid of glandular components and composed only, as its name suggests, of muscle and fibrous tissue. Screening may be considered in men ages 55 to 69 with the knowledge that it will prevent about one cancer death for every 1,000 men screened. Expert guidelines don't recommend PSA screening in men 70 and older. Because of their more limited lifespan, these men are less likely to benefit from early detection of low-risk cancer. The American Cancer Society recommends annual examination with digital rectal examination and serum PSA beginning at age 50 and for men with a life expectancy of at least 10 years after detection of prostate cancer. For men in high-risk groups, such as African Americans or men with a first-degree relative diagnosed at a younger age, testing sexual activity that includes ejaculation. bike riding often or a recent long bike ride. Prostate-specific antigen (PSA) is a protein made by the cells of the prostate gland. PSA is mostly found in semen, but it is also normal to find small amounts of PSA in the blood of healthy men. A PSA test measures the amount of PSA in the blood. Upper limit of normal (ULN) for prostate-specific antigen was recommended as 4 ng/mL when it was firstly introduced into clinical practice. This cut-off value was based on serum PSA measurements of 860 healthy men. Upper limit of normal of age-adjusted median PSA values for various age groups have been determined as follows: 0.7 ng/mL (40 .

psa normal range by age