There is currently no specific level of prostate-specific antigen that is universally considered abnormal. Doctors previously recommended biopsies for patients with PSA levels of over 4.0 nanograms per milliliter of blood, according to the National Cancer Institute.
The previously accepted threshold may not correlate to whether or not a patient has prostate cancer. Generally, a high and rising PSA level may signify prostate cancer, reports the National Cancer Institute. However, unrelated factors, such as urinary tract infections and prostatitis, often raise PSA levels, as do prostate biopsy and surgery. On the other hand, drugs used to treat benign prostate hyperplasia lower PSA levels.