Prostate-Specific Antigen (PSA)
How It Feels
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
There is very little chance of a problem from
having a blood sample taken from a vein.
- You may get a small bruise at the site. You can
lower the chance of bruising by keeping pressure on the site for several
- In rare cases, the vein may become swollen after the blood
sample is taken. This problem is called phlebitis. A warm compress can be used
several times a day to treat this.
- Ongoing bleeding can be a
problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and
other blood-thinning medicines can make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell
your doctor before your blood sample is taken.
A prostate-specific antigen (PSA) test
measures the amount of
prostate-specific antigen in the blood.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Because normal PSA levels seem to increase
with age, age-specific ranges may be used. But the use of age-specific ranges
is controversial, and some doctors prefer to use one range for all ages. For
this reason, it is important to discuss your test results with your
A follow-up test that measures free prostate-specific
antigen (free PSA) may be used to see if a prostate biopsy should be done to
check for cancer. Free PSA is prostate-specific antigen that is not attached to proteins in the blood. The lower a man's free PSA level, the more likely he is to
develop prostate cancer.
Free prostate-specific antigen (fPSA)2
Percent free PSA
Probability of cancer
More than 25%: