What is PSA and what is it used for?
PSA stands for Prostate Specific Antigen, a protein produced by the prostate gland. It is used to detect prostate cancer and to monitor the effectiveness of prostate cancer treatment. (NB: a high PSA does not automatically mean you have cancer, see below. On rare occasions, the test can be normal even if a person does have cancer.)
How is it tested?
PSA can be detected in the blood and is tested using a blood sample from a vein in your arm. As part of the testing, your doctor will need to examine you by inserting a gloved, lubricated finger into the anus to feel the prostate. There should be a chaperone present during this procedure.
When is it done?
Testing for PSA is usually done when a person has symptoms of an enlarged prostate. These can include:
- Weak or dribbly urinary stream
- Feeling like you can’t completely empty your bladder
- Difficulty starting urination
- Urinating frequently or more often than normal (especially at night)
- Straining when urinating
- Dribbling urine when not in the toilet
What do my results mean?
What is normal varies according to your age:
A high PSA may be a sign of prostate cancer, however having a high PSA doesn’t automatically mean you have cancer.
What is high also varies according to your age but these values are still very variable depending on things like ethnicity, family history, overall health.
Other conditions can cause a raised PSA, including:
- Being unable to pass urine, leading to an enlarged bladder (acute urinary retention)
- Non-cancerous (benign) prostate enlargement
- Increasing age
- Urinary tract infections
- Inflammation of the prostate (acute prostatitis)
- Surgery on the prostate
- Having a tube to help pass urine (catheter)
Temporary rises in PSA can be caused by ejaculation, vigorous exercise, rectal examination, and receptive anal sex. Drugs such as aspirin, statins, diuretics, cyclophosphamide, methotrexate, finasteride and dutasteride can also affect the PSA – always tell your healthcare professional if you are taking any medications so they can account for this in the PSA results.
What happens after the PSA test?
If your PSA level is raised, you may be referred to a specialist for further testing to work out if you have cancer or not. This might include a prostate biopsy, where a sample is taken for analysis. If your level is only slightly raised, you may not need referral but you may need a few more PSA to confirm you’re okay.