There is no level of PSA (prostate-specific antigen) in the blood that is considered normal, according to the National Cancer Institute. However, it is typical for higher levels to be indicative of prostate cancer, particularly if PSA levels continue to rise over time.
PSA levels are recorded in nanograms (ng) per milliliter (mL) of blood. It was formerly considered that a PSA test result of 4.0 ng/mL or above was abnormal and indicative of prostate cancer, according to the National Cancer Institute. However, data has more recently shown that prostate cancer occurs in men whose PSA test result is lower than 4.0 ng/mL. Likewise, it is possible for men with higher levels of PSA not to have prostate cancer.