PSA Test (Prostate Specific Antigen)

  • Medical Author:
    Kevin C. Zorn, MD, FRCSC, FACS

    Dr. Kevin Zorn is a dual-board-certified (US and Canada), minimally-invasive uro-oncology, fellowship trained urologist at the University of Chicago. His main focus of clinical and scientific interest is in the surgical treatment of renal and prostate cancer. He is also an expert in performing surgery with the DaVinci Surgical Robotic System to manage localized prostate cancer and small renal masses. Dr. Zorn studied medicine and urology at McGill University in Montréal.

  • Medical Author: Pierre-Alain Hueber, MD, PhD
  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

View the Prostate Cancer Slideshow Pictures

4KScore Test

The 4K biomarker is a blood test that measures four different proteins in the blood to assess prostate cancer risk. The blood test that assesses these biomarkers is called the 4KScore Test. It suggests the possible risk that a significant prostate cancer would be found.

The 4Kscore Test relies on the measurement of four prostate-specific kallikreins in the blood:

  • Total PSA,
  • Free PSA,
  • Intact PSA, and
  • Human Kallikrein 2 (hK2).

Quick GuideMen's Health: Essential Screening Tests Every Man Needs

Men's Health: Essential Screening Tests Every Man Needs

Prostate specific antigen (PSA) test facts

  • The PSA test is a blood test.
  • The PSA test can be used to suggest the presence of prostate cancer, to monitor its treatment, or assess its recurrence.
  • The PSA test can also be abnormal with benign enlargement (benign prostatic hyperplasia or BPH), inflammation (prostatis), and infection of the prostate gland.

What is prostate specific antigen (PSA)?

Prostate specific antigen (PSA) is a substance produced exclusively by certain cells within the male prostate gland. Biochemically, it belongs to the protease family of kallikrein and is also known as human kallikrein 3 (hK3). PSA is secreted by the prostate in the semen where its role is to liquefy the semen following ejaculation. Most of the PSA produced by the prostate gland is carried out of the body in semen, but a very small amount escapes into the blood stream, so PSA is normally found in low amounts (nanograms per milliliter or ng/mL) in the blood.

If the PSA level is high for your age or is steadily increasing (with or without an abnormal physical exam), further investigation, namely a prostate biopsy, may be recommended. The doctor should consider other risk factors of prostate cancer such as family history, prostate volume, the presence of benign prostatic hyperplasia (BPH), urinary symptoms, rectal exam findings, and ethnicity before recommending the biopsy. At this time, prostate biopsy for pathology review is the only way to determine if prostate cancer or other abnormal cells are present in the prostate.

How is PSA test measured?

PSA is measured by a simple blood test that does not require fasting or special preparation. Since the amount of PSA in the blood is very low, detection of it requires a very sensitive type of technology (monoclonal antibody technique). The PSA protein can exist in the blood by itself (known as free PSA), or bound with other substances (known as bound or complexed PSA). PSA is mostly bound to three substances: alpha-2-macroglobulin, alpha 1-antichymotrypsin (ACT), and albumin. Total PSA is the sum of the free and the bound forms. The total PSA is what is measured with the standard PSA test.

Medically Reviewed by a Doctor on 1/14/2016

Subscribe to MedicineNet's Cancer Report Newsletter

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.

VIEW PATIENT COMMENTS
  • PSA Test - Patient Experience

    What were the results of your PSA test and how did your doctor proceed in light of the results?

    Post View 22 Comments

Health Solutions From Our Sponsors