PSA Test

The PSA test is a blood test used to screen for prostate cancer. It measures the amount of prostate-specific antigen (PSA) in your blood. PSA is a protein produced by both cancerous and noncancerous tissue in the prostate. PSA is mostly found in semen; small amounts ordinarily circulate in the blood.

High levels of PSA may indicate the presence of prostate cancer; however, many other conditions (such as an enlarged or inflamed prostate) can also increase PSA levels. Therefore, interpreting a “high” PSA can be complicated.

Interpreting PSA Levels

PSA level increases with age (about 0.04 ng/mL per year) due to increased prostate volume; age-specific reference ranges should be considered when interpreting PSA values.1

Common Reasons PSA May Be Elevated

• Prostatitis (inflammation of the prostate)2
• Urinary tract infection2
• Benign enlargement of the prostate (BPH)2
• Recent physical activity or sex2

Other Factors That Influence PSA

• Advancing age
• Recent urological procedures
• Use of testosterone-enhancing drugs
• Obesity
• Certain medications (e.g., aspirin or cholesterol-lowering agents)
• Use of finasteride (hair-growth drug)

Limitations of the PSA Test

• Up to ~15% of prostate cancers occur with PSA < 4 ng/mL.2
• False-positive results are common; some studies report rates as high as 46.8%.2
• Only about 25% of men biopsied for elevated PSA are found to have prostate cancer.4
• False-positives are more likely in men aged 61–70 and >70 than in those <45.3
• “Normal” cut-offs were largely derived from studies of white males and may not generalize to all racial groups.2

A Comprehensive Approach to Prostate Health

As research continues to refine our understanding of the PSA test’s merits and limitations, it’s best viewed as one part of a broader strategy. Regular physical examinations, individual risk assessment, and informed discussions with your healthcare provider should guide decisions—and consideration of prostate MRI may also be appropriate.

Note: This information is educational and not a substitute for personalized medical advice. Always consult your clinician about your specific situation.

Sources

1. Raychaudhuri, Ruben, Lin, Montgomery (2025). Prostate Cancer: A Review. JAMA; 333(16):1433–1446. doi:10.1001/jama.2025.0228.
2. PSA False Positive and False Negative Results, News Medical Life Sciences.
3. Variables Associated with False-Positive PSA Results: A Cohort Study with Real-World Data, National Library of Medicine.
4. National Cancer Institute.