What is a Prostate-Specific Antigen (PSA)?
Prostate-specific antigen, or PSA, is a protein produced by normal, malignant, cells of the prostate gland. The PSA test measures the level of PSA in a man’s blood. For this test, a blood sample is sent to a laboratory for analysis. The results are usually reported as nanograms of PSA per milliliter (ng/mL) of blood.
Why would I need this test?
PSA test is used to screen for prostate cancer. Screening is a test that looks for a disease, such as cancer, in its early stages, when it's most treatable. Therefore you may get a PSA test if you have certain risk factors for prostate cancer. These include:
- Men with a family history of prostate cancer
- Your age: Prostate cancer is more common in men over the age of 50.
- Being African: Prostate cancer is more common in African men. The reason for this is unknown.
You may also get a PSA test if:
- You have symptoms such as painful or frequent urination, and pelvic and/or back pain.
- You've already been diagnosed with prostate cancer. The PSA test can help monitor the effects of your treatment.
How do I prepare for a PSA test?
If our doctors requests that you should have a PSA test, make sure that they are aware of any prescription or medicines, vitamins, or supplements you take. Certain drugs may cause the test results to be falsely low.
If our doctors thinks your medication might interfere with the results, they may decide to request a different test or they may ask you to avoid taking your medicine for several days so your results will be more accurate.
How is a PSA performed?
- You are required to sit upright in a chair and rest your arm face up on an elevated arm rest. The will tie a strap (tourniquet) around the top of your arm to temporarily restrict the blood flow from your arm back to your heart. This will make the vein inside your elbow “pop out”, and therefore easier to find. The area where the needle will be inserted is wiped with a sterile alcohol wipe to reduce any risk of infection. A needle is inserted into the vein and a small amount of blood is drawn into the vial attached to the needle.
- If seeing blood makes you uneasy, it is best to look away. Usually the phlebotomist will ask you questions as they take the blood to distract you from the procedure. It is done in no time! If there is any pain at all, it is minimal. More often than not, you will only feel a slight discomfort.
- After the procedure, the phlebotomist will press a small wad of cotton on the entry point to stop the flow of blood. The cotton wad is strapped on with a band aid. This only needs to remain on for a couple of hours. Sometimes a little bruise is left in this spot, but this is nothing to worry about.
What do the results of my PSA test mean?
In general, a PSA level that is above 4.0 ng/mL is considered suspicious. However, there are many other factors to consider before taking further action. The following are some general PSA level guidelines:
- 0 to 2.5 ng/mL is considered safe
- 6 to 4 ng/mL is safe in most men but talk with our doctors about other risk factors
- 0 to 10.0 ng/mL is suspicious and might suggest the possibility of prostate cancer. It is associated with a 25% chance of having prostate cancer.
- 0 ng/mL and above is dangerous and should be discussed with our doctors immediately. It is associated with a 50% chance of having prostate cancer.
If Your PSA is High
Talking to our doctors can explore several options if your PSA is high. One option is to have a second PSA screening; recent research has shown that a second screening can improve the accuracy of an abnormal result. A digital rectal exam (DRE) and a biopsy can also confirm the presence or absence of prostate cancer. However, there are several other reasons why a PSA result might be high:
- Advanced age
- Recent biopsy
- Catheter
- Injury to pelvic region or prostate
- Prostatitis
- Riding a bicycle
- Sex (within the past 24 hours)
- Supplements that effect testosterone
- Urinary tract infection
If Your PSA is Rising Quickly
The rate in yearly increase in the PSA level is known as the PSA velocity. This is one measure of prostate cancer risk, since PSA levels can rise rapidly in men who have prostate cancer. This can be especially useful to find prostate cancer in early stages before the cancer has left the capsule of the prostate.
PSA result between 4.0 and 10.0 ng/ml is an early indicator of prostate cancer if a man.
>What are the risks of a PSA test?
Drawing blood is considered safe. However, because veins and arteries vary in size and depth, getting a blood sample is not always simple.
The healthcare professional who draws your blood may have to try several veins in multiple locations on your body before they find one that allows them to get enough blood.
Drawing blood also has several other risks. These include risk of:
- Fainting
- Excessive bleeding
- Feeling lightheaded or dizzy
- An infection at the puncture site
- A hematoma, or blood collected under the skin, at the puncture site.
