Prostate Specific Antigen (PSA) is a protein produced by the prostate gland, a small organ in the male reproductive system located below the bladder. This protein circulates in the blood.
Understanding Prostate Specific Antigen
Prostate Specific Antigen is produced primarily by the epithelial cells within the prostate gland. It is secreted into the seminal fluid, where its main biological function is to liquefy the seminal coagulum after ejaculation. This liquefaction allows sperm to move freely, aiding in fertility.
While most PSA remains in the seminal fluid, a small amount can escape the prostate and enter the bloodstream. Normal prostate cells, as well as those affected by certain conditions, produce PSA. Its presence in the blood can therefore offer insights into prostate health.
Purpose of the PSA Test
A PSA test measures the level of prostate-specific antigen in the blood. This test serves as a screening tool for prostate cancer, detecting potential issues early. Early detection may allow for more timely management if cancer is present.
The test also monitors men diagnosed with prostate cancer, tracking disease progression or assessing treatment effectiveness. It also helps investigate non-cancerous prostate conditions, such as an enlarged prostate or inflammation. The PSA test is a screening tool and does not provide a definitive diagnosis of cancer on its own.
Interpreting PSA Test Results
PSA test results are reported in nanograms of PSA per milliliter of blood (ng/mL). There is no single “normal” PSA level, as it varies by age and other individual factors. Lower PSA levels are generally associated with a lower likelihood of prostate cancer.
A PSA level below 1 ng/mL is often considered very low. Levels between 1 and 3 ng/mL are generally within a safe range for many men. A PSA level above 4.0 ng/mL is often considered elevated and may prompt further evaluation.
Levels above 10.0 ng/mL are considered significantly elevated and are associated with a higher probability of prostate cancer. The interpretation of PSA levels always considers a man’s overall health, age, and other risk factors to provide a comprehensive assessment.
Factors Influencing PSA Levels
Several non-cancerous factors can cause PSA levels to rise temporarily or persistently. Age is a common factor, as PSA levels tend to increase gradually with age due to natural prostate growth.
Benign prostatic hyperplasia (BPH), a non-cancerous enlargement of the prostate, is a frequent cause of elevated PSA levels because the increased prostate tissue produces more PSA. Prostatitis, an inflammation or infection of the prostate gland, can also lead to a temporary spike in PSA as the inflamed tissue may release more of the protein into the bloodstream.
Other factors include recent ejaculation or vigorous physical activity like cycling, which can temporarily increase PSA levels. Urinary tract infections (UTIs) and certain medical procedures, such as a digital rectal exam (DRE) or a prostate biopsy, can also cause PSA to rise. It is recommended to avoid these activities for at least 48 hours before a PSA test for more accurate results.
Next Steps After an Elevated PSA Result
If a PSA test result is elevated, the next steps involve further evaluation to determine the cause. A healthcare provider may recommend a repeat PSA test to confirm the initial finding, as levels can fluctuate due to various factors. This repeat test helps account for temporary elevations.
A digital rectal examination (DRE) is often performed alongside or after a repeat PSA to check for any physical abnormalities of the prostate. Additional tests might include a “free PSA” test, which measures the ratio of unbound PSA to total PSA, potentially helping to distinguish between benign conditions and cancer. Imaging studies, such as a multiparametric MRI of the prostate, may also be ordered to visualize the gland and identify suspicious areas.
If concerns for prostate cancer remain after these evaluations, a prostate biopsy is typically recommended. This procedure involves taking small tissue samples from the prostate for microscopic examination to definitively diagnose or rule out cancer. The decision to proceed with any of these steps is made in discussion with a healthcare provider, considering individual risk factors, symptoms, and personal preferences.