Prostate-specific antigen, or PSA, levels tend to increase with age, according to the National Cancer Institute. Because of this, some doctors have suggested using age-specific PSA reference ranges as a screening tool for prostate cancer, although these ranges have not been adopted as of 2015.
Current guidelines suggest that a PSA level between 1 and 4 nanograms per milliliter, or ng/mL, is normal for men of all ages, according to MedicineNet. Because the prostate gland tends to grow with age and produce more PSA as it grows, it is also normal for older men to have higher normal levels of PSA and younger men to have lower levels.
When looking at PSA levels in determining risk for prostate cancer, doctors also pay special attention to the change in PSA readings over time, notes MedicineNet. The change in PSA levels over time, which is medically referred to as PSA velocity, is a big determinant in decision making when it comes to PSA markers. A normal PSA increase of less than 0.75 ng/mL can be the deciding factor in whether counseling on management is required or if disease should be suspected. A 50 to 59-year-old man with a PSA velocity of 0.50 to 2.5 ng/mL may be cause for concern, even if his levels are still within normal range.