Prostate-Specific Antigen (PSA) is a protein primarily produced by the cells within the prostate gland, a small gland located below the bladder in males. PSA’s natural function involves liquefying semen to allow sperm mobility. While a small amount of PSA is normally present in the blood, elevated levels can indicate prostate conditions, including prostate cancer. The PSA test measures the concentration of this protein in the blood, serving as a screening tool to help detect potential prostate issues. It is often a first step in evaluating prostate health.
Common Causes of Elevated PSA
Elevated PSA levels can stem from several non-cancerous factors, sometimes leading to misinterpretation as prostate cancer. A common cause is benign prostatic hyperplasia (BPH), a non-cancerous enlargement of the prostate gland. As the prostate grows, it produces more PSA, raising blood levels.
Prostatitis, an inflammation or infection of the prostate, can significantly raise PSA levels. This inflammation disrupts prostate cells, allowing more PSA to leak into the bloodstream. Any recent physical manipulation of the prostate can also cause a temporary increase in PSA.
A digital rectal exam (DRE), where a doctor manually examines the prostate, can lead to a temporary PSA elevation. For this reason, it is often recommended to have blood drawn for a PSA test before a DRE, or at least a few days after. Recent ejaculation can also cause a temporary rise in PSA, so individuals are advised to abstain for 24 to 48 hours before the test.
More invasive procedures, such as a prostate biopsy or surgery, cause a substantial but temporary increase in PSA due to direct tissue trauma. PSA levels can remain elevated for weeks or even months. Vigorous physical activity, particularly cycling, can also temporarily irritate the prostate, resulting in a modest PSA increase.
Factors That Can Lower PSA
Certain factors can artificially lower PSA levels, potentially masking an underlying prostate condition. Medications called 5-alpha reductase inhibitors (5-ARIs), such as finasteride and dutasteride, are commonly prescribed for BPH or hair loss. These drugs reduce dihydrotestosterone production, which influences prostate growth and PSA, thereby lowering PSA levels by approximately 50%.
Individuals with a higher body mass index (BMI), often associated with obesity, may also have lower PSA levels. This is partly due to hemodilution, where increased blood volume in obese individuals dilutes PSA concentration. This can make accurate interpretation of PSA results challenging in this population.
Some herbal supplements, such as saw palmetto, have been anecdotally linked to lower PSA levels. However, scientific evidence supporting a significant and consistent impact is often limited or mixed. Their influence on PSA readings is not as well-established as the effects of prescription medications.
Steps for an Accurate PSA Test
To ensure the most accurate PSA test result, individuals should take specific preparatory steps. Inform your healthcare provider about all medications, including prescription drugs and over-the-counter supplements, that you are currently taking. Discussing any recent medical procedures, such as a prostate biopsy or cystoscopy, is also important.
Avoid ejaculation for at least 24 to 48 hours before the test, as this can temporarily elevate PSA levels. Similarly, refrain from vigorous exercise, especially activities like cycling that put direct pressure on the prostate, for two to three days prior to the blood draw. Physical irritation can lead to a transient PSA increase.
Proper test scheduling is also beneficial. Avoid a PSA test immediately after a digital rectal exam. If you have recently undergone a prostate biopsy or prostate surgery, your doctor will likely recommend waiting several weeks or even months for PSA levels to stabilize before testing.
Understanding Your PSA Results
A PSA number alone does not definitively diagnose prostate cancer. The result must be interpreted within the broader context of an individual’s overall health, medical history, age, and family history. A PSA test is a screening tool; an elevated result indicates the need for further evaluation, not a cancer confirmation.
Many factors, both cancerous and non-cancerous, influence PSA levels. Therefore, a comprehensive discussion with a healthcare provider is essential to understand your result. Your doctor will consider all relevant information and may recommend additional tests, such as a repeat PSA test, digital rectal exam, or prostate biopsy, to determine the underlying cause of elevated levels.