What Is PSA? A Complete Guide to Prostate-Specific Antigen

Updated: May 21, 2025 | By Dr. Pawan Gaba

🧬 What is PSA?

Prostate-Specific Antigen (PSA) is a glycoprotein enzyme produced primarily by cells in the prostate gland. PSA plays a role in semen liquefaction, aiding sperm motility. While it is normal to have small amounts of PSA in the bloodstream, elevated levels may indicate underlying prostate conditions such as:

Benign Prostatic Hyperplasia (BPH)
Prostatitis (prostate inflammation)
Prostate Cancer

📈 PSA Reference Ranges

Age Group	Normal PSA Range (ng/mL)
40–49 years	0–2.5
50–59 years	0–3.5
60–69 years	0–4.5
70–79 years	0–6.5

🧪 Types of PSA Tests

Total PSA: Measures total PSA in blood.
Free PSA: Measures unbound PSA. A lower ratio indicates higher cancer risk.
PSA Density: PSA level divided by prostate volume (via ultrasound).
PSA Velocity: Measures rate of change in PSA over time.
Prostate Health Index (PHI): Combines total PSA, free PSA, and [-2]proPSA.

⚠️ Limitations of PSA Testing

PSA testing has false positives and negatives. Elevated PSA doesn't always mean cancer. Conversely, normal PSA levels don't rule it out. Hence, additional evaluations may include:

Digital Rectal Exam (DRE)
Transrectal Ultrasound
MRI of the prostate
Prostate biopsy

🧓 Public Awareness: Joe Biden’s PSA & Prostate Cancer Story

On May 16, 2025, former U.S. President Joe Biden was diagnosed with metastatic prostate cancer at the age of 82. According to an NPR report, Biden’s cancer had spread to his bones and had a high Gleason score of 9/10. Fortunately, it was hormone-sensitive, allowing him to benefit from androgen deprivation therapy (ADT).

This diagnosis underscores the importance of regular PSA screening, especially in older men. Although PSA screening after age 70 is debated, Biden’s case shows how early and continued monitoring can still influence treatment outcomes, even in advanced age.

📌 Screening Guidelines

Men aged 50+: Annual screening recommended.
Men aged 40–49: Recommended if family history or African descent.
Men 70+: Screening based on individual risk-benefit discussion.

✅ How to Prepare for a PSA Test

Avoid ejaculation 48 hours prior.
Do not cycle or perform heavy physical activity before the test.
Inform your doctor of urinary symptoms or infections.
Avoid PSA test if you've had a DRE in past 24 hours.

💬 Final Thoughts

PSA remains a vital but complex biomarker for prostate health. While not perfect, it continues to be central in screening and monitoring prostate conditions. Informed decisions and discussions with healthcare providers are essential.