PSA (Prostate-Specific Antigen)

What is PSA?

Prostate-Specific Antigen (PSA) is a protein produced by the prostate gland. It's found in small amounts in the blood of all men. PSA testing is used primarily to screen for prostate cancer.

Why is it Important?

PSA testing helps:

• Screen for prostate cancer
• Monitor prostate cancer treatment
• Detect benign prostatic hyperplasia (BPH)
• Assess prostate inflammation (prostatitis)

Normal Ranges by Age

Age Group	Normal Range	Unit
Men < 50 years	0 – 2.5	ng/mL
Men 50-59 years	0 – 3.5	ng/mL
Men 60-69 years	0 – 4.5	ng/mL
Men ≥ 70 years	0 – 6.5	ng/mL

What Do Abnormal Results Mean?

Elevated PSA (> 4.0 ng/mL)

Common causes include:

• Prostate cancer (risk increases with higher PSA)
• Benign prostatic hyperplasia (BPH, enlarged prostate)
• Prostatitis (prostate inflammation or infection)
• Recent ejaculation or prostate exam
• Urinary tract infection
• Prostate biopsy or surgery
• Vigorous exercise (cycling, horseback riding)

PSA and Cancer Risk

PSA Level	Cancer Risk
0 – 2.5 ng/mL	Low (~7%)
2.5 – 4.0 ng/mL	Moderate (~15%)
4.0 – 10 ng/mL	~25%
> 10 ng/mL	> 50%

Important: Elevated PSA does NOT mean you have cancer. Further testing (MRI, biopsy) is needed.

Free PSA vs Total PSA

• Total PSA: All PSA in blood
• Free PSA: Unbound PSA (not attached to proteins)
• Free PSA %: (Free PSA / Total PSA) × 100

Free PSA percentage interpretation:

• > 25%: Lower cancer risk (likely BPH)
• 10-25%: Intermediate risk
• < 10%: Higher cancer risk

PSA Velocity and Doubling Time

• PSA velocity: Rate of PSA increase over time (ng/mL/year)
• PSA velocity > 0.75 ng/mL/year: May indicate cancer
• PSA doubling time < 3 years: Higher cancer risk

Screening Recommendations

• Age 50-69: Discuss PSA screening with your doctor (shared decision-making)
• Age 45-49 (high risk): Consider screening if Black or family history of prostate cancer
• Age 40-44 (very high risk): Consider screening if multiple family members had early prostate cancer
• Age > 70: Routine screening generally not recommended

Factors That Can Affect PSA

Increase PSA:

• Prostate manipulation (exam, catheterization)
• Ejaculation (within 48 hours)
• Vigorous exercise
• Urinary tract infection

Decrease PSA:

• Medications: Finasteride (5-alpha reductase inhibitors)
• Aspirin or statins (long-term use)
• Obesity

When Should You Get Tested?

PSA testing may be ordered if you have:

• Difficulty urinating or weak urine stream
• Frequent urination, especially at night
• Blood in urine or semen
• Pelvic discomfort
• Family history of prostate cancer
• Monitoring after prostate cancer treatment