PSA (Prostate Specific Antigen)
Definition
PSA is a protein produced by the prostate gland. The prostate is a gland in the male reproductive system located just below the bladder. The test measures the level of PSA in the blood.
Purpose
Screening for and monitoring prostate cancer. Screening means looking for signs of cancer before symptoms appear.
Results
Critical:
There is no specific normal or abnormal level of PSA in the blood. In general, the higher the PSA level, the greater the likelihood of cancer.
However, a high PSA does not prove that cancer is present.
Normal Values
There is no numerical threshold, as the source explicitly states. This must be included in the glossary so that patients do not fall into a false sense of security such as "my PSA is below 4, so I must be fine".
Risks and Limitations
Non-cancerous causes of elevation:
- Benign prostatic hyperplasia (BPH)
- Prostatitis (inflammation of the prostate)
- Urinary tract infection
- Certain medications
The screening debate: PSA screening is optional and may lead to unnecessary biopsies and treatments, whose possible harms include erectile dysfunction, urinary incontinence and fecal incontinence. Personal risk factors, overall health and preferences should be discussed with a physician.