Skip to content
Select An Article
Font Size

Prostate-Specific Antigen (PSA) Blood Test

(continued)

When Should I Have My PSA Levels Tested?

The American Cancer Society says men should talk to their doctors about the benefits, risks, and limitations of prostate cancer screening before deciding whether to be tested. The group's guidelines make it clear that prostate-specific antigen (PSA) blood testing should not occur unless this discussion happens. They recommend that most men at average risk for prostate cancer start the discussion at age 50 and those with higher risk for prostate cancer should start the discussion earlier.  

The American Urological Association recommends that men ages 55 to 69 who are considering screening should talk with their doctors about the risks and benefits of testing and proceed based on their personal values and preferences. The group also adds:

  • PSA screening in men under age 40 years is not recommended.
  • Routine screening in men between ages 40 to 54 years at average risk is not recommended.
  • To reduce the harms of screening, a routine screening interval of two years or more may be preferred over annual screening in those men who have decided on screening after a discussion with their doctor. As compared to annual screening, it is expected that screening intervals of two years preserve the majority of the benefits and reduce over diagnosis and false positives.
  • Routine PSA screening is not recommended in men over age 70 or any man with less than a 10-15 year life expectancy.

The U.S. Preventive Services Task Force, however, doesn't recommend routine PSA screening for men in the general population, regardless of age. They say the tests may find cancers that are so slow-growing that medical treatments -- which can have serious side effects -- would offer no benefit. 

If your doctor is concerned that you might have prostate cancer based on either a PSA level or a rectal exam, a biopsy (a lab testing of a small amount of tissue from the prostate) will be the next step. This is the only way to positively identify the presence of cancer.

What Does an Elevated PSA Level Mean?

Elevated PSA levels may indicate prostate cancer or a noncancerous condition such as prostatitis or an enlarged prostate.

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.

 

Next Article:

Today on WebMD

man with doctor
Symptoms, risks, treatments
man coughing
Men shouldn’t ignore
 
prostate cancer cells
What does this diagnosis mean?
doctor and male patient
Is it worth it?
 
cancer fighting foods
SLIDESHOW
15 Cancer Symptoms Men Ignore
FEATURE
 
Prostate Enlarged
VIDEO
Picture Of The Prostate
ANATOMY
 
Prostate Cancer Quiz
QUIZ
screening tests for men
SLIDESHOW
 
Prostate Cancer Symptoms
VIDEO
Vitamin D
SLIDESHOW