Prostate-Specific Antigen (PSA) testing is a common screening tool used to assess prostate health, often initiated as part of routine physical examinations. This blood test measures a protein produced by the prostate gland, and its value is interpreted alongside other factors to determine potential risks. An elevated PSA reading frequently causes concern, as it is associated with prostate cancer, but a high number is not a definitive cancer diagnosis. Understanding the numerous factors that can temporarily or permanently elevate PSA levels, including various types of infections, is important for accurate assessment.
What PSA Measures
Prostate-Specific Antigen is a protein enzyme produced by the epithelial cells within the prostate gland. Its biological function is primarily related to fertility, where it acts as a serine protease to liquefy semen after ejaculation, allowing sperm to move freely. While most PSA remains in the seminal fluid, a small amount leaks into the bloodstream, which is what the blood test measures.
The level of PSA circulating in the blood is measured in nanograms per milliliter (ng/mL) and serves as a marker of prostate activity. When the prostate gland is disturbed or inflamed, more of this protein is released into the bloodstream, causing the measured level to rise. Therefore, an elevated reading indicates a problem within the prostate, such as inflammation or enlargement, but it does not specify the underlying cause.
How Infection Affects PSA Levels
Infections can significantly raise PSA levels because they cause inflammation of the prostate gland, a condition known as prostatitis. The inflammatory response is the body’s attempt to fight the infection, which disrupts the prostate’s cellular structure. This disruption leads to a breakdown of the barrier between the prostate tissue and the bloodstream, allowing a larger volume of PSA to leak out.
Acute bacterial prostatitis typically causes the most dramatic and rapid spike in PSA levels. Once treatment, usually antibiotics, is successfully administered, the inflammation subsides. The PSA level is expected to return to its baseline within approximately four to six weeks.
Systemic viral infections can also lead to elevated PSA readings, either through direct interaction with prostate tissue or as a result of a generalized inflammatory response. Certain viruses, such as those causing infectious mononucleosis or COVID-19, have been observed to correlate with temporary PSA increases. This is often an indirect effect, where the body’s overall inflammatory state influences the prostate.
Non-Infection Factors That Raise PSA
Aside from infection, the most common non-cancerous factor for elevated PSA is Benign Prostatic Hyperplasia (BPH). BPH is the natural, non-malignant enlargement of the prostate that occurs with age. As the gland increases in size, it produces more PSA due to the greater volume of tissue. Elevated PSA levels are also a natural consequence of aging, even in the absence of disease, as the prostate gradually grows over time.
Physical manipulation of the prostate can also cause a temporary, measurable rise in the protein’s level. For this reason, patients are advised to abstain from sexual activity and intense exercise for 24 to 48 hours before a blood draw.
Factors that can irritate the gland and lead to a short-term elevation include:
- Vigorous exercise, particularly cycling that puts pressure on the perineum.
- Recent ejaculation.
- A digital rectal exam (DRE).
- The insertion of a catheter.
- A prior prostate biopsy, which necessitates waiting several weeks before a reliable retest.
Certain medications, like 5-alpha reductase inhibitors used to treat BPH, can artificially lower PSA, which a physician must account for during interpretation.
Diagnostic Follow-Up After High Readings
When a patient receives an elevated PSA result, the physician reviews the patient’s history to identify and manage any potential confounding factors, such as a recent infection or physical activity. The standard recommendation is to wait four to six weeks to allow temporary causes of elevation to resolve before retesting the PSA level. This initial delay helps prevent unnecessary further procedures.
If the PSA remains elevated, the physician may employ secondary blood tests for a more detailed understanding of the prostate’s condition. These tests include calculating the PSA velocity, which measures the rate of change over time, and determining the percentage of “free PSA.” The free PSA percentage compares unbound PSA to the total PSA in the blood. A lower percentage is associated with a higher likelihood of cancer, while a higher percentage is linked to benign conditions.
Further investigation involves multiparametric Magnetic Resonance Imaging (mpMRI) to visualize the prostate gland and identify suspicious areas. If the mpMRI reveals suspicious lesions, or if the PSA velocity and free PSA percentage suggest a higher risk, a prostate biopsy is recommended. Consultation with a urologist or healthcare provider is necessary for a personalized diagnosis and management plan.