Interpreting Your PSA Level
Prostate cancer screening starts with a blood test for prostate specific antigen (PSA). It can help catch the disease at an early stage when you have more treatment options and a better chance of cure. During a PSA test, a small amount of blood is drawn from the arm, and the level of PSA is measured.
Historically, many physicians used a PSA of 3 or 4 as the borderline between “normal” and “abnormal.” We now realize this assessment is more complicated, and a high PSA doesn’t always mean cancer. A high PSA may be due to infection or inflammation of the prostate (prostatitis), prostate growth, or another benign cause. PSA increases with age, and your PSA should be compared with normal values for men in your age group. For example, the average PSA for younger men (aged 40–49) ranges from 0.5–0.7 ng/mL, and men with a PSA above the median are at higher risk of later developing prostate cancer. However, it is important to understand that a PSA above 3 or 4 may suggest the need for further testing, such as imaging, other blood tests, or a biopsy.
A small but important proportion of men are at increased risk of prostate cancer due to them carrying an inherited cancer risk gene mutation (e.g., BRCA2) or having a strong family history of cancer. People with at least one first-degree relative (such as a father or brother) who has/had prostate cancer may start PSA screening earlier.
In rare cases, men who have a very low PSA may still have clinically significant prostate cancer. Unfortunately, in most of these cases, disease does not present until it has progressed beyond the prostate and become symptomatic. Your urologist will consider your PSA levels in light of all of these factors.
Last Reviewed: 12/2023
