The prostate produces a protein called prostate specific antigen (PSA). The role of PSA is to make semen more fluid and so help sperm swim more easily. It’s normal to find PSA in a man’s blood as some PSA ‘leaks’ naturally leaks out of the prostate. The level of PSA in the blood can be raised by more PSA finding its way out of the prostate into the blood stream, if the prostate walls becoming weakened or damaged by a disease in the prostate. The greater the leakage, the higher the PSA level is likely to be in the man’s blood. The PSA level can be checked by your GP by means of a simple blood test. A raised PSA level however, can be for a number of reasons and doesn’t necessarily mean the man has prostate cancer:
- Age. As a man ages the higher his PSA level is likely to be;
- Benign prostatic hyperplasia or BPH. This is enlargement of the prostate.
- Prostatitis. This inflammation or infection in the prostate
- Prostate cancer;
- Urinary tract infections (UTI);
- After a prostate biopsy
- Inspections of the bladder using cystoscopies;
- If you have exercised energetically in the last 48 hours;
- Significant levels of cycling (more than 10 miles/day on a regular basis);
- If you have ejaculated in the last 48 hours.
Having a UTI, biopsy, cystoscopy, exercising vigorously, cycling or ejaculating only raise PSA for a short period of time and the level should go back to its more normal level when the infection is treated or after a period of abstinence.
What is the normal level for PSA?
To some extent this depends on your age. The older you get, the higher your PSA level is likely to be. The doctor who gets your PSA results will take this into account. In some areas, there may be slight differences in the levels used.
- Age 40-49 years ~ 2.5 ngms/ml
- Age 50-59 years ~ 3.0 ngms/ml
- Age 60–69 years~ 4.0 ngms/ml
- Age 70+ years ~ 5.0 ngms/ml
The man’s PSA level is useful in telling doctors which treatments may benefit patients with benign and malignant prostate diseases, who needs to be examined further for prostate cancer, and for monitoring treatment for prostate cancer.
A PSA test may find prostate cancer at an early stage when it can be detected by no other means and even when there are no other symptoms at all. Conversely, not all men who have a raised PSA level will have prostate cancer. If prostate cancer is diagnosed, the PSA test can be very valuable in checking how well treatments are working.
PSA circulates in 2 forms in the blood. One type is linked to a second protein, while the other is ‘free’. As part of the PSA test, the amount of ‘free’ PSA, which is not linked, may also be measured. This is because a lower amount of ‘free’ PSA may indicate prostate cancer and a higher amount is more likely to indicate benign prostate growth. A percentage level of ‘free’ PSA below 18 is more likely to indicate prostate cancer.
About the PSA level
Your PSA level is not raised – In all probability no further action will be taken. You might find that you will be asked to have another PSA test to confirm the result at a later date especially if you are over 50 or have a brother or father who has/had prostate cancer.
Your PSA level is raised – You will need some further tests including more PSA tests and your doctor may want to do a DRE.
Your GP may refer you to a specialist for further tests such as a prostate biopsy to check for disease in the prostate. Once a diagnosis is made, you will be given lots of information in order that you and your doctor can decide on the type of treatment that is right for you.
Are there any times when I shouldn’t have the test done?
PSA levels can be affected by several things so may give a false high level of PSA in your blood. Let your doctor know if any of these apply to you and put off having the test:
- If you have an active or have had a recent urinary infection
- If you have ejaculated in the last 48 hours
- If you have exercised energetically in the last 48 hours
- If you have had a prostate biopsy in the last 6 weeks
- If you have had a DRE (Digital Rectal Examination) in the last week
- If you have had a prostate massage
- Tell your doctor about any medications or herbal remedies you are taking
Free PSA in your blood.
PSA travels in the blood in two forms:
- Unattached to a protein in the blood called Free PSA
- Attached or bound to a protein in the blood called Bound PSA
The Free PSA test measures the proportion of unattached or Free PSA to the total amount of PSA in your blood sample. It is thought that a higher amount of free PSA in a test means a lower chance of having prostate cancer.
PSA doubling time
If you have been diagnosed with prostate cancer and decided to manage it by Active Surveillance, or you have had a radical prostatectomy or radiotherapy treatment your PSA will be checked regularly. A single, one-off rise in your PSA level may be due to other reasons, such as an infection. If your doctors notice that the level is continuing to go up, they will look at how quickly and by how much it has gone up.
If your PSA level doubles in less than 3 years (called your PSA doubling time) then, your doctor will discuss this with you as it may be a sign that your prostate cancer is becoming more aggressive.
If your PSA rises, even though it doesn’t actually double, it may be that your doctor advises that active surveillance is no longer a suitable management for your prostate cancer.
There is a leaflet about the PSA test here. Further information about PSA is available in this booklet: PSA Explanatory-booklet.
To keep a record of PSA level, Gleason score, prognostic grade group, scans, appointments etc, you may find the Prostate Log Book helpful as you note results down and keep them all in one place.