Does intercourse affect Prostate-Specific Antigen (PSA) levels?

Effect of Intercourse on PSA Levels

Ejaculation can temporarily increase PSA levels, and patients should abstain from ejaculation for 48 hours before PSA testing to ensure more reliable results. 1

Impact of Ejaculation on PSA Testing

The National Comprehensive Cancer Network (NCCN) guidelines specifically address this issue, stating that PSA results are more reliable if a patient has abstained from ejaculation for 48 hours prior to testing. If this condition is not met and the PSA result is marginally elevated, the test should be repeated after 48 hours of abstention 1.

Mechanism and Evidence

When examining the evidence:

• Ejaculation causes a significant increase in serum PSA concentration in men between 49-79 years of age 2
• This elevation can persist for up to 48 hours after ejaculation 2
• The magnitude of increase appears to correlate with:
  • Patient age
  • Baseline PSA level

Timing of PSA Changes After Ejaculation

Research shows a specific pattern of PSA changes following ejaculation:

• Both total and free PSA increase immediately after ejaculation 3
• Mean total PSA levels can remain significantly elevated at 6 and 24 hours after ejaculation 3
• Approximately 40% of men still have elevated total PSA levels 24 hours after ejaculation when accounting for normal biologic variation 3

Clinical Implications

This temporary elevation in PSA has important clinical implications:

• False positive results could lead to unnecessary prostate biopsies
• Unnecessary patient anxiety about potential prostate cancer
• Additional healthcare costs for follow-up testing

Recommendations for Clinical Practice

To ensure accurate PSA testing:

1. Advise patients to abstain from ejaculation for at least 48 hours before PSA testing
2. If a PSA result is marginally elevated and the patient has ejaculated within 48 hours, repeat the test after appropriate abstention
3. Document sexual activity history when interpreting borderline PSA results

Other Factors Affecting PSA Levels

For comprehensive understanding, other factors that can affect PSA levels include:

• Prostatitis
• Benign prostatic hyperplasia
• Urethral or prostatic trauma
• Medications (finasteride and dutasteride can lower PSA by approximately 50%)
• Prostate biopsy (can cause substantial PSA elevation for 3-6 weeks)
• Vigorous exercise, particularly cycling, in the 2 days prior to testing 1

Conclusion

When conducting PSA testing as part of prostate cancer screening or monitoring, healthcare providers should instruct patients to abstain from ejaculation for at least 48 hours before blood sampling to minimize the risk of false-positive results and ensure the most accurate interpretation of PSA values.