What is PSA?
One important part of the male reproductive system is the prostate gland. This gland is an organ roughly the size of a walnut. It is situated below the urinary bladder and surrounds a tube called the urethra. The urethra is connected to the bladder and runs through the penis. Urine travels through the urethra in order to exit the body. Seminal fluid, which contains sperm cells and substances that nourish them, passes through the urethra as well.
Along with other glands surrounding the urethra, the prostate produces substances that make up the seminal fluid. One of the substances produced by the cells in the prostate is a protein called prostate specific antigen (PSA). It contributes to the reproductive capability of men. Aside from the seminal fluid, some amounts of PSA may also be found in the blood.
You may have a blood test to measure how much PSA is in your blood. This is your total PSA level. An elevated PSA level may be a sign that something is affecting your prostate.
What is a normal PSA level?
Your total PSA level may also be affected by your age and ethnicity. PSA levels tend to rise as a man gets older. Your doctor can interpret your PSA test results based on what is the appropriate PSA level for your age, ethnic group, and other factors.
In general, a normal total PSA level is less than 4.0 nanograms (ng) of PSA per milliliter (ml) of blood. If your total PSA level is more than 10 ng/ml, prostate cancer is more likely. However, some men with elevated PSA results have been found not to have prostate cancer. There have also been cases wherein men with a total PSA level below 4.0 ng/ml were later on diagnosed with prostate cancer.
Other conditions may raise your total PSA level. If you have a total PSA level of 4.0 to 10 ng/ml, your prostate may be affected by any of the following conditions:
- Cancer
- Benign prostatic hyperplasia (BPH). This is a condition wherein your prostate enlarges. Usually, a bigger prostate produces more PSA, resulting in a higher total PSA level. An enlarged prostate can press on your urethra. This may cause symptoms such as problems with urinating. However, BPH is not prostate cancer.
- Acute bacterial prostatitis. This means that your prostate has become inflamed due to a bacterial infection.
- Procedures such as a digital rectal examination (DRE), biopsy of the prostate, or prostate surgery.
Aside from your total PSA level, your signs and symptoms will tell your doctor what is most likely affecting your prostate. After having a test for your total PSA level, your doctor may also examine your prostate for any irregularities in size or shape with a DRE. Your doctor may recommend additional tests. From there, you and your doctor will decide together how to proceed with regard to further testing and treatment, if necessary.
What are other tests for PSA aside from the total PSA level?
PSA is found in your blood in two forms. It may be attached to other proteins (also known as the “bound” form) or it may be floating freely in the blood (known as the “free” form). The total PSA level is a measurement of all the PSA in your blood, regardless of whether it is free or bound.
Some studies recommend measuring the free form of PSA after having a total PSA level blood test. The free PSA test may be useful if your total PSA level is within the range of 4.0-10ng/ml. If you have a low free PSA level but an elevated total PSA, there is a higher chance that you may have prostate cancer. A high free PSA level means prostate cancer is less likely. Your doctor may also check how much free PSA you have compared to your total PSA level in order to see if other tests, such as a biopsy, may be needed.
Another test that may be useful if your total PSA level ranges from 4.0 to 10 ng/ml is PSA density. This test compares the volume of your prostate to your PSA level. The volume of your prostate is measured using ultrasound. This test may be used by your doctor to differentiate between prostate cancer and BPH.
There are also other tests related to PSA that may help your doctor know more about what is happening with your prostate. You may have one or all of the following tests:
- PSA velocity. This test measures how much your PSA level rises or falls over a certain period of time. The PSA velocity can be used to monitor the presence of prostate cancer. If your PSA levels keep on rising over time, you may have a higher chance of having prostate cancer. The PSA velocity may also indicate if you have an aggressive form of the disease. If your PSA level increases very quickly in a short amount of time, an aggressive prostate cancer may be present.
- PSA doubling time. This test measures how quickly your PSA level doubles.
Generally, a high PSA level means that there may be something wrong with your prostate. However, a high PSA level is not necessarily a cause for alarm. It simply means that further investigation may be necessary. Discuss your concerns about PSA with your doctor.