What Is a PSA Score?

A prostate-specific antigen (PSA) score shows the levels of a protein called protein-specific antigen in the blood, according to the National Cancer Institute. The PSA test is the diagnosis tool that is used to find this score in people being screened for prostate cancer.

Use

• The PSA score is used to detect prostate cancer during its early stages. The National Cancer Institute states the score is used to diagnose prostate cancer in men 50 years old and older or in patients with recurring forms of cancer.

Test

• During a PSA test, a doctor starts by performing a blood test on a patient. The person's blood is then sent to a laboratory, where levels of prostate-specific antigens are measured.

PSA Score Results

• A normal PSA level is lower than 4.0 nanograms per millimeter, according to the National Cancer Institute. If a patient has a PSA level of 4.0 ng/ml to 10.0 ng/ml, his doctor will often perform an X-ray, biopsy or digital rectal exam to further determine if he has prostate cancer.

Other PSA Score Meanings

• Drcatalona.com states irregular PSA scores can also signal a patient has benign prostatic hyperplasia, prostatitis or prostate trauma. Some healthy men older than 50 have elevated levels of prostate-specific antigens.

Types of Antigens

• There are two types of prostate-specific antigens, ones that are free-floating and others that are attached to a protein. People with higher levels of the latter type are more likely to have prostate cancer.