A PSA Blood Test (prostate-specific antigen test) may be done as a result of findings during a digital prostate exam or may be done as a stand-alone test. It is not unusual for your family physician to make PSA testing part of the overall screening that you’ll have done as a normal course of an annual physical. This is especially true if you’ve reached the age of 40.
The PSA blood test requires a normal blood draw that we’ve probably all experienced at one time or another in our lives. Within a few days, your results come back from the laboratory, and you’re discussing results with your doctor.
However, it is at least as important to speak with your doctor before proceeding with the testing. In keeping with recommendations from the American Cancer Society (ACS), pre-test discussions are important because the PSA blood test, in and of itself, is not foolproof. There are many factors that may affect your PSA number. A figure of 4 ng/ml or higher may not necessarily be a guarantee of the presence of prostate cancer. Conversely, a figure of less than 4 ng/ml does not mean that you are cancer free. There are limitations associated with the results of the PSA blood test and it’s important to keep in mind that it is one screening method along a path of several that are done to gain a complete insight as to the nature of your condition – if you have a condition at all. ACS guidelines explicitly recommend that pre-testing discussions on these matters take place between you and your physician. Elevated PSA levels may also indicate noncancerous conditions including prostatitis or an enlarged prostate gland.
The only way to confirm the presence of prostate cancer is through a biopsy. A biopsy is going to be recommended if preliminary screening methods (the prostate exam and PSA blood testing) give your medical team cause for concern and further investigation. A biopsy involves the removal of a small sampling of tissue from the prostate gland which is sent to a medical laboratory for analysis.
Factors that may affected your Prostate-Specific Antigen (PSA) Level include:
- Age is a factor. This is because your PSA levels normally will go up with age, sometimes even when prostate cancer isn’t present.
- Medications are a factor. Medications including Propecia, Proscar, and Avodart (finasteride and dutasteride) can falsely reduce PSA levels. If you’re taking such medications, it’s very important that you disclose this to your medical team.
- Recent sexual activity is a factor. Doctors often recommend that you abstain from sexual activity in the days leading up to a PSA blood test as it can increase PSA levels in the blood.
- A prostate infection can be a factor by causing PSA levels to rise.
In addition to the PSA blood test, there are other PSA tests that are helpful to guide both the determination of prostate cancer and guide the treatment thereof if a formal diagnosis is made.
Percent-free PSA Test: Prostate-specific antigen takes two major forms in the bloodstream. One binds to blood proteins. The other freely circulates in the bloodstream. A percent-free PSA test indicates how much PSA circulates free in comparison to the total PSA level. For men who have prostate cancer, the percentage of free PSA is lower. Studies show that if your PSA results are in the 4 ng/ml to 10 ng/ml range, a percent-free PSA of under 10% means that your likelihood of having prostate cancer is about 50%. In such cases, a biopsy is likely to be highly recommended. Doctors often recommend prostate gland biopsies when the percent-free PSA results indicate 20% or less.
PSA Velocity Test: While not actually a separate test, it is the monitoring of PSA bloos tests to track the change in your PSA levels over a period of time. Even when the total PSA value isn’t greater than 4 ng/ml, when your PSA velocity is high (an change greater than .75 ng/ml in a year), it may be indicative of prostate cancer presence and further testing, usually a biopsy, is likely.