Prostate-Specific Antigen (PSA) Testing
The 1980s witnessed the discovery of the blood test for Prostate Specific Antigen (PSA). Testing a blood sample for the amount of PSA now plays an important part in the early detection of prostate cancer. If an abnormally high level of PSA is detected in the blood, prostate cancer is a possibility. However, a high PSA score does not always indicate cancer and can be caused by other prostate diseases such as benign prostatic hypertrophy (BPH) or prostatitis (inflamed prostate).1
Prostate-specific antigen (PSA) is a substance made by the normal prostate gland. Although PSA is mostly found in semen, a small amount is also present in the blood. Most men have levels under 4 nanograms per milliliter (ng/mL) of blood. When prostate cancer develops, the PSA level usually goes above 4.2 If your level is above 4 but less than 10, you have about a 25% chance of having prostate cancer. If it goes above 10, your chance of having prostate cancer is over 50% and increases as your PSA level increases.3
Your PSA will normally go up slowly as you age, even if you have no prostate abnormality. Ejaculation can cause a temporary increase in blood PSA levels, so some doctors will suggest that men abstain from ejaculation for two days before testing. Several medicines and herbal preparations can lower blood PSA levels. You should tell your doctor if you are taking Finasteride™ (Proscar™ or Propecia™).
Saw Palmetto (an herb used by some men to treat benign prostate enlargement) does not seem to interfere with the measurement of PSA. PC-SPES and some other herbal mixtures "for prostate health" may affect PSA levels, which is why it is important to let your doctor know if you are taking any type of supplement.
If a PSA level is higher than normal, a biopsy of the prostate may be done. Complications from a biopsy of the prostate may include fever, pain, blood in the urine or semen, and urinary tract infection. Even if a biopsy shows that a patient does not have prostate cancer, he may worry more about developing it in the future.
False-negative test results can occur. Screening test results may appear to be normal even though prostate cancer is present. A man who receives a false-negative test result may delay seeking medical care even if he has symptoms.
False-positive test results can also occur. Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result can cause anxiety and is usually followed by more tests, which may have risks. Your doctor can advise you about your risk for prostate cancer and your need for screening tests.1
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