The Prostate-Specific Antigen (PSA) Blood Test
Your PSA level can also be affected by other factors:
If your PSA level is high, your doctor may recommend that you get a prostate biopsy to test for cancer.
There are some new PSA tests that may help you and your health care provider determine if you need a biopsy. You should know that doctors do not always agree on how to use or analyze the results of these additional tests.
In this article
- How Is The PSA Screening Test Done?
- When Should I Have My PSA Levels Tested?
- What Does an Elevated PSA Level Mean?
- Alternative PSA Testing
- Using the PSA Blood Test After Prostate Cancer Diagnosis
What Does an Elevated PSA Level Mean? continued...
Your PSA level can also be affected by other factors:
- Age. Your PSA will normally go up slowly as you age, even if you have no prostate problems.
- Medications. Some drugs may affect blood PSA levels. Tell your health care provider if you are taking finasteride (Proscar or Propecia) or dutasteride (Avodart). These drugs may falsely lower PSA levels typically by half of what it would normally be.
If your PSA level is high, your doctor may recommend that you get a prostate biopsy to test for cancer.
Alternative PSA Testing
There are some new PSA tests that may help you and your health care provider determine if you need a biopsy. You should know that doctors do not always agree on how to use or analyze the results of these additional tests.
- Percent-free PSA. PSA takes two major forms in the blood. One is attached, or bound, to blood proteins and the other circulates freely. The percent-free PSA test indicates how much PSA circulates free compared to the total PSA level. The percentage of free PSA is lower in men who have prostate cancer than in men who do not. Studies show that if your PSA results are in the borderline range (4 to 10), a low percent-free PSA (less than 10%) means that the likelihood of having prostate cancer is about 50% and that you should probably have a biopsy.
Many doctors recommend biopsies for men whose percent-free PSA is 20 or less. - PSA velocity. The PSA velocity is not a separate test. Rather, it is the change in PSA levels over time. Even when the total PSA value isn't higher than 4, a high PSA velocity (an increase greater than 0.75 ng/mL in one year) suggests that cancer may be present and a biopsy should be considered.
- Urine PCA3 test. This urine test looks for a fusion of genes that is present in 50% of PSA-tested men with prostate cancer. It's another tool to determine if a man may need a biopsy.
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